This is how my friends are setup.closet with shower pan and drain is so useful for all the mentioned things. Wet clothes, extra storage, rinse off, potty spot, etc.
adjacent to their entry door. Its basically a mudroom / shower / toilet room.
Its only built in fixtures is showerhead, splashproof cabinet and railway sink.
Toilet is either cassette or bucket of sawdust.
Btw, it has a sizable opening window also.