Set/configure "nude appearance" (and a bonus appearance question)

[picket]

I'm sorry if this has been asked a hundred times before, I'm sure it was, but is there a way, WW or not, to define a Sim's "nude appearance"?
E.g. a female Sim's everyday outfit features a fancy updo hairstyle, but when she strips down for a shower or sex I'd like her hair to be open, or maybe makeup to disappear - is there a way?

 

Not related to this or WW, but also reg. appearance: When my unplayed Sims are used as random townies walking the streets, they're often dressed in ridiculous clothes regardless all the outfits I configured for them - is there a way to stop this and let them actually wear the clothes I gave them when they show up randomly? I'm not sure if this is a basegame thing or MCCC, but I'd really like them to stop doing it, total immersion killer.

Edited January 27 by picket