Would it be possible to add doom 64 support? you could use doom 64 ex or Nevander's gzdoom port doom 64 Retribution
The doom64ex engine is a pain to work with, as each map has to be inside its own wad, and I don't own the doom64 rom, so I cannot even test it until I buy that rom.
Personally I just ain't very interested in Doom64, I just don't like that game very much.
Version 4.28 of OBLIGE could build maps for the Absolution TC which runs on an old version of Doomsday engine. So you can try that, though 4.28 maps are pretty poor.