is craft studio capable of character customization (such as either uploading a custom skin or even choosing looks, clothing and proportions, even limb replacement)? Its for a few games I am developing.
You should ask in the project's own comments or community, as the case may be. If they don't have either, at least link to the project page so we know what you're talking about. This forum is for discussing Itch.io itself.
Craftstudio is an engine on here, and their forums got wrecked a few years ago by a bunch of spammers. They don't have a community of their own anymore. It was abandoned.
PS: The page seems to be vacant. It is such a good engine, why did it die so early?