>>5064724well removing something or just texturing is pretty much as simple as removing something with file explorer. you dont even really need to remove anything as you could just make a alpha texture, a lot of asian mods do it nowadays(one model cut into several ones with alphas)
the things you described on a scale from 1 to 10, 1 being sleepwalking and 10 being hard would be a -2 so i suggest just grabbing some 3d modeling suite and getting used to the basic controls and what not, everything carries over to HS.
modelling clothes themselves from scratch is more of a "the more time you put into it the better it will look" type of deal, 3 workflows i can think of, 1. polygonal modelling, just adding things there and there and then sub diving 2. sculpting 3. marvelous designer, i do a lot of 2. and 3. in combination and i add 3d coat in there to uv map, texture and retopologize(make something that would burn your computer not burn your computer)
#mod-creation channel if you need any help