I would love to make my res warm ocean, but I don't see it in the list. Will the new biomes ever be available for our res?
They probably are! The list probably wouldn't have been updated yet, but I can't see a reason for why the new biomes would not be allowed, if all (or pretty much all) previously existing biomes are.
I always kinda wanted "Hell" and "The End" to be added due to my Ambiance mods adding in custom sky boxes for those biomes and it would make the aesthetic all the more grand
I supposed these might not be allowed, that's why I added in "(or pretty much all)" in my post above. But yeah, it'd be interesting. What grass colour do those biomes have, I wonder? I wasn't able to find it online. Oh, and of course 1.16 will add several new Nether biomes! Anyway, I can imagine having these biomes in the overworld may cause issues. I'm not sure.
"Hell" and "The End" have the same grass color as dry biomes. So that yellowish, brown color. They actually don't cause any problems since some staff-event residences have these as biomes.