"Innumerable meanings derive from one Law", doesn't mean that any base or mistaken concept is Buddhism.
"Draw your own conclusions from what I said above. Those among my followers who fail to carry through their faith to the end will incur punishment even more severe. Even so, they should not harbor a grudge against me. Remember what fate Sho-bo, Notobo, and others met." -- The Hero of the World
"Yet, for all that, [some people associated with Ota Jomyo distort the teaching]. I cannot fathom what could be in their minds." -- The Four Bodhisattvas as Object of Devotion
"The priest Nichigyo’s (Sammibo) death was indeed pitiful. I recited the Lotus Sutra and chanted Namu-myoho-renge-kyo for him here in Minobu, sincerely praying to Shakyamuni, Many Treasures, and the Buddhas of the ten directions to receive him on Eagle Peak. I have not yet recovered from my illness, so I have written only briefly. I will write to you again." -- Four Bodhisattvas as the Object of Devotion
"Even those who are free from illness cannot escape the transience of life, but you are not yet old, and because you are a votary of the Lotus Sutra, you will not meet an untimely death." -- The Bow and Arrow
“Those who do not understand their obligations will in many cases meet with an untimely death." -- On Consecrating an Image of Shakyamuni Buddha Made by Shijo Kingo
"There is one thing to be thankful for. Kagenobu, Enchi, and Jitsujo all died before Dozen-bo did, and that was something of a help. These men all met an untimely death because of the chastisement of the ten demon daughters who protect the Lotus Sutra. After they died, Dozen-bo began to have some faith in the Lotus Sutra. But it was rather like obtaining a stick after the fight is over, or lighting a lantern at midday— the proper time had already passed." -- Repaying Debts of Gratitude
"The deaths of Ota Chikamasa, Nagasaki Jiro Hyoe-no-jo Tokitsuna, and Daishin-bo, who were all thrown from their horses, can be seen as punishment for their treachery against the Lotus Sutra." -- On Persecutions Befalling the Sage
"There was something very strange about Sammi-bo. Nevertheless, I was concerned that any admonition would be taken by the ignorant as mere jealousy of his wisdom, and so I refrained from speaking out. In time his wicked ambition led to treachery and, finally, to his doom. If I had scolded him more strictly, he might have been saved. I have not mentioned this before because no one would have understood it. Even now the ignorant will say that I am speaking ill of the deceased. Nevertheless, I mention it so that others can use it as their mirror. I am sure that our opponents and the renegades are frightened by the fate of Sammi-bo." -- Ibid.
"Some people criticize me, saying, 'Nichiren does not understand the capacities of the people of the time, but goes around preaching in a harsh manner—that is why he meets with difficulties.' Other people say, 'The practices described in the "Encouraging Devotion" chapter are for bodhisattvas who are far advanced in practice; [Nichiren ought to follow the practices of] the "Peaceful Practices" chapter, yet he fails to do so.' Others say, 'I, too, know the Lotus Sutra is supreme, but I say nothing about it.' Still others complain that I give all my attention to doctrinal teachings. I am well aware of all these criticisms against me. But I recall the case of Pien Ho, who had his legs cut off at the knee, and of Kiyomaro (Pure Man), who was dubbed Kegaremaro (Filthy Man) and almost put to death. All the people of the time laughed at them with scorn, but unlike those two men, those who laughed left no good name behind them. And all the people who level unjust criticisms at me will meet with a similar fate. The 'Encouraging Devotion' chapter says, 'There will be many ignorant people who will curse and speak ill of us.' I observe my own situation in this passage. Why should it not apply to all of you as well? 'They will attack us with swords and staves,' the passage continues. I have experienced this passage from the sutra with my own body. Why do you, my disciples, not do likewise?" (pg. 209)
The SGI teaches "Lesser doctrines", ie: Value creationism; human revolution; shoju in the degenerate age and towards those who would destroy the Lotus Sutra; mentor-disciple as the prime point of the Lotus Sutra; the inequality of those who chant the Daimoku; the purpose of the Juryo-hon is to smash the Hoben-pon and the purpose of Daimoku is to smash the Juryo-hon; Nichiren is True Buddha; Namu Myoho renge kyo is true Buddha; Nam Myoho renge kyo rather than Namu Myoho renge kyo; the Lotus Sutra has lost it's efficacy in Mappo; the common man can not understand the Lotus Sutra or Gosho in Mappo; prayers repaying one's debt of gratitude to the Three Presidents rather than that owed Shakyamuni Buddha; the Nichikan Gohonzon; personal guidance; the list goes on and on. The concept, "innumerable meanings derive from one Law", doesn't mean that any base or mistaken concept is Buddhism.
The One Vehicle is Myoho renge kyo:
"Thus it was that the eight-year-old dragon girl was able to come out of the vast sea and in an instant give proof of the power of this sutra, and Superior Practices, a bodhisattva of the essential teaching, emerged from beneath the great earth and thereby demonstrated the unfathomably long life span of the Buddha. This is the king of sutras, defying description in words, the wonderful Law that is beyond the mind’s power to comprehend." (Embracing the Lotus Sutra)
Nichiren does indeed teach, "Never seek this Gohonzon outside yourself. The Gohonzon exists only within the mortal flesh of us ordinary people who embrace the Lotus Sutra and chant Namu-myoho-renge-kyo." but he also teaches that the mandala Gohonzon (the life and land of Original Eternal Buddha Shakyamuni) is the teacher of the Buddhas throughout the Three Existences:
"If it is not the proper Object of Worship (Gohonzon), even though there be no falsehood [even if the practitioner is sincere] it will not form the seed [of Buddhahood]. The Daimoku of the Hommon [Doctrine of the Original, found in the Lotus Sutra] is the seed of Buddhahood. This is because the Eternal Shakyamuni of the Honmon has put his Causal Practices (his myriad practices that lead to enlightenment) and his Virtues of the Effect (the merits of the effect, which is Buddhahood) into the seven characters of Namu Myo Ho Renge Kyo." (The True Object of Worship)
"If one doubts the strength of the Buddha when he says, “I am the only person who can rescue and protect others”; if one is suspicious of the rope held out by the Lotus Sutra when its teachings declare that one can “gain entrance through faith alone”; if one fails to chant the Mystic Law which guarantees that “such a person assuredly and without doubt [will attain the Buddha way],” then the Buddha’s power cannot reach one, and it will be impossible to scale the embankment of enlightenment." (Embracing the Lotus Sutra)
and again, it is not enough merely to believe in and chant the Mystic Law:
"Only when one understands all this clearly and believes in it can the Law manifest its power and the Buddhas and bodhisattvas bring benefit to the people. To illustrate, in kindling a fire, three things are needed: a good piece of steel, a good flint, and good tinder. The same is true of prayer. Three things are required— a good teacher, a good believer, and a good teaching— before prayers can be effective and disasters banished from the land.
A good teacher is a priest who is free from any fault in secular affairs, who never fawns upon others even in the slightest, who desires and is satisfied with little, and who is compassionate; a priest who reads and upholds the Lotus Sutra precisely as it teaches and also encourages and leads others to embrace it. Such a priest the Buddha has praised among all priests as the finest teacher of the Law.
A good believer is one who does not depend upon persons of eminence or despise those of humble station; who does not rely on the backing of superiors or look down on inferiors; who, not relying upon the opinions of others, upholds the Lotus Sutra among all the sutras. Such a person the Buddha has called the best of all people.
As for a good teaching, the Buddha has told us that this sutra, the Lotus, represents the foremost among all doctrines. Among all the sutras the Buddha “has preached,” among those he “now preaches,” and among those he “will preach,” this sutra is designated as foremost, and therefore it is a good teaching." (How Those Initially Aspiring to the Way Can Attain Buddhahood).
Even a good believer is insufficient if the teacher and teachings are mistaken and SGI's "great good" of planting seeds too is unfounded. Their seeds are damaged seeds because their Object of Worship and teacher is damaged [mistaken]. They may sprout and look like beautiful saplings but as they mature, they grow into the crooked trees of the Taisekeji teachings.