“However, if R’ Elyashiv said that they are apikursim, you cannot demand that the Halacha be changed”
Rambam didn’t include that as an ikkar of faith. Neither did R’Hasdai Crescas. Nor did R’Yosef Albo. It appears in none of the lists of 613 mitzvot. Does an Acharon have the power to change halachah by adding an ikkar?