I think if possible I'd personally like dungeon rarity configs (chunks, blocks radius), abillity to disable specific dungeons (sky, underground, forest and underwater) and abillity to disable what pets can spawn on these said dungeons.
This all just personal preferance for a modpack I'm making, but some pets seem a little OP and I want them to be crafted instead of found. Also, with the dungeons so close together, I feel you could potentially have all the pets within an hour if you wanted. I also agree with the pets being split across dimensions, or at least just the nether. But if mods added biomes, a way to tell it to allow them to spawn more widely throughout would be pretty awesome.
I know it's a lot, but that's my 2 cents.
Also, the name Solar_Tiger originated from my wife giving me the pet name Tiger and solar just came from me being her light, so to speak. But I like your idea, and may use it down the road.