I guess you should check out the Solarus project for Action-RPG games: https://www.solarus-games.org/
especially got used for Zelda-related fan games, but also got been used for other games too.
If you want to simply apply the custom resources over SMBX Vanilla to keep their original AIs, that would go simpler. You should verify the names of files you do use.
In another case, If you want to make the Zelda-related game using PGE Engine by complete replacing of resources include the logic, you will need to build the new config pack from the scratch using graphics and making lua code using PGE Lua API to program NPC-AI for your new elements, etc. At the same time, PGE Engine is still being WIP and it was been on a long hiatus (with keeping minor fixes and tweaks on it), however, soon I gonna rework it majorly with using the experience I got while the TheXTech development and research of the vanilla SMBX game.
Some useful links for you:
Keep the note that the logic of every playable character and every NPC requires you to code lua. Also, even the P-Switch is a lua-coded logical thing.
On another note, PGE Engine does use the different format of per-level configs (it prefers the modern INI files to vanilla TXT), use the Config Pack specification and the "per-item configuration" paragraphs where the explanation on these INI files.