It's possible to play as masklings with a very small tweak to the data files. TestMod actually does this, so you can enable it if you want to try them out.
Maskling's aren't playable by default, however, because they're pretty boring right now. They don't have any resources to worry about, or anything to trade.
I tried that out. Fun, but difficult. I now have a greater appreciation for walls. I've been trying to mod in a new barracks (stables) and a new unit (cavalry). Got the files and pictures sorted out, but it won't let me import them into the compressed Base File folder. Will it work if I put them into an unzipped file called base mod?
I'm assuming mushroom people will have a tech level between Masklings and Humans.
You shouldn't modify BaseMod. Instead there is a folder called mods. You can zip up the files and put them in there, along with a manifest file. There are two mods distributed with Bronze Age that you can use as examples. You can also distribute the mod zip file. I'd be interested in seeing it myself.
