Some thoughts for criticism:

Nichiren had moved to Minobu in 1274. Hakiri Sanenaga built Kuonji for him in 1281, the year before he passed away. It was about “ten-ken square (one ken measures about six feet).” Nichiren named it ” Minobusan Kuon-ji Myohokkein Temple.”
Of the location, Rev. Teijo Kunugi wrote: “It [Minobusan Kuonji Temple] remained in Nishidani Valley (western valley) for about 200 years, until it was moved to its current location at the time of Gyogakuin Niccho (1422-1500), who was the 11th chief abbot of Kuon-ji Temple. The reason for the move,according to Niccho, was that the place in the western valley was geographically narrow for the temple and was always in danger from natural disasters.”
I suspect that “One Buddha and Four Attendents” {Isson Shishi} Statues were enshrined as the Honzon there. Here is a painting from circa 1334: IIRC, the painting is intended to depict one of Hakiri Sanenaga’s sons and wife visiting Nichiren at the original Minobusan Kuonji in 1281/82. Notice the Gohonzon?
I also think the original statues were maybe damaged or destroyed; circa 1283 or 1284. This may have been the last straw for Nissho & Nichiro; causing them to give up on Minobu? In other words, this may have been the event that caused the already shaky “rotation system” to collapse. Nissho and the others may have concluded that Minobu, at least the oroginal valley, was not a safe location, and that the Landlord Hakiri Sanenaga was unable or unwilling to make it safe.
Nikko wrote “The Reply to Mimasaka” by Nikko on October 12 1284. In that letter, he alludes to a falling out between the Landlord and Nissho. Here is an excerpt; “The Shonin told me in his will: “If the steward Hakiri turns his back to the Law, my spirit will cease to reside in Minobu.” I have not observed any particularly inappropriate behavior on his part, however. … how can one even posit the notion that the Shonin’s spirit does not reside in Minobu?
Also, it appears most of the 18 disciples assigned to the rotation refused to go there. Nissho and Nichiro had removed the Chu Hokekyo and standing statue of Shakya that Nichiren wanted kept at the mausoleum. They probably did this to keep them safe.
Hakiri Sanenaga may have resented the intrusion of 18 diiciples building residences in the Nishidani Valley. Perhaps he was angered over demands that he build a proper mausoleum. This is from Hakiri Dono Goho {Report to Lord Hakiri}, Sep 1282, Nichiren’s last recorded Gosho, transcribed by Nikko, and kept at Ikegami:
“I eventually plan to return to Mt. Minobu, but since I am now ill, nothing is certain about what may happen to me at any given time and place. No words can ever describe the magnitude of your kind support over a period of nine years, when people all over the nation of Japan hated and persecuted me. Thus, wherever I may meet my demise, I would like to be buried in the valley of Minobu. … No matter where I die, please erect my tombstone at Mt. Minobu, where I chanted the Lotus Sutra in peace for nine years. My heart will go on to stay on Mt. Minobu forever.”
Apparently, this had not been planned out. Hakiri Sanenaga had placed himself
at risk by allowing Nichiren to stay there. He was not excessively wealthy — it took him 8 years to even build the temple. Moroever, while that valley was great for a retreat; it was a terrible place for a busy Temple Complex, and an unsafe place to protect sacred artifacts.
As of late 1284, this mausoleum either had not been built at all; or was in ill repair. Nikko wrote: “More than anything else, it is absolutely deplorable that the Shonin’s grave site in the valley of Minobu has totally dilapidated from neglect and is defaced by the hoof tracks of deer. ” ibid
to be cont’d