Many things are possible with scripting, but such a thing needs scripting. What I usually do is I find a mod or a place in the game where something happens that I want to replicate, which in your case would be an NPC changing clothing. I'm not sure if I can think of any such events off the top of my head though. Perhaps the lady in Vault 21, she changes into sleepwear when you, uh, charm her. Might just be replacing her with a new (temporary) NPC though. You could try to see if there's any commands for refreshing inventory at the GECK wiki, and then look into making a script that counts the in-game days and refreshes after a while. In theory that should mean a new outfit each time it is refreshed, so long as they have a levelled list with multiple entries.
WCP would probably undo all my changes, and thus, ironically, be very incompatible.