I wanted to make the NTM canisters work together with the Flans, but I do not know how to do it. I tried to do it through Minetweaker, but nothing worked because of the peculiarity of the code.

There's not an easy way to do that I'm afraid, the mod will only accept fuel cans that inherit from ItemPart
https://github.com/Unknown025/Flans-Mod-Plus/blob/Ultimate/src/main/java/com/flansmod/common/parts/ItemPart.java

There is some compatibility with RF fuel sources? But I'm not sure how that works, or if it works.