As much as I like hats - I do have one on in my avatar, after all - I probably *won't* include them just because they're always really awkward to add to a model that can have all kinds of different hairstyles... It usually requires redrawing every hairdo to have a 'with a hat on' version, which is a pain, especially when it wouldn't even work with every style of hat. Males will also have antlers, which will very much get in the way!
I will keep them NAKED like this for the actual game, since, well, they have fur, and it's not the same as a naked human, at least to me. I think of it as nudity in the same way that this is!
[link] (whose name also includes 'Acorn', come to think of it; I did not have that character in mind when designing this character or these cervids though!)
And I think underwear would look weird... I might make characters comment about you walking around nude, though!
You'll START the game nude, actually, and will have to get dressed (there'll be three different sets of shirts and pants in Acorn Nose's room to choose from, letting you customise right from the start rather than her having a default outfit), but she might refuse to go outside unless you put something on first.
I did make this model thinner than the one in that image. That thing has a line going down its side, as a part of the top, and I cut the torso off there. I know it's doing what I said I didn't want to and portraying an unrealistic level of slimness, but at least it's not nearly as bad as Pokemon humans!