For both the trees when you break the leaves in survival, with any tool (including fist) you get the leaves back instead of saplings.

Baobab saplings won't produce a tree, even with bone meal.

Minecraft Version 1.17.1
Mod Version v2.0.0-alpha.12
Fabric Version 0.11.6

I also forgot to add, there are no "generic" crafting recipes for either wood. (can't craft sticks, chests, crafting tables, etc.)

Huh... the leaves drop table should be about the same as vanilla (as I used vanilla methods to create it) but perhaps I glossed over something. Same with the other recipes not working.
Baobab saplings need to be in a 4x4 arrangement due to their sheer size. A single sapling or 2x2 won't work.

I did try with the 4x4 initially, but after a couple of minutes of trying it didn't work, though that could just be me.

Fixed in latest alpha