Can you assign uniforms for a shop?
What you CAN do is set up the restaurants as owned businesses using the Open For Business expansion. Have a sim buy the business, hire staff, then set each employee's uniform. You can set the owner's uniform too. Then send the owner home, leaving the business empty. You can do this for each restaurant, even using the same owner sim if you want... can give the owner a different uniform in each business. Other sims can then travel to the businesses and use them as normal community lots - your owner will be there as an NPC, as will the staff dressed in their selected uniforms.
Incidentally, businesses run pretty darn well this way. It's a great way to cheat at OFB - just let the game run the business automatically and rack up stars.
From what I've found from playing businesses in general, it's always possible to set the business clothing for *all* employees, playable AND non-playable. Now the NPCs (such as the restaurant cook and server) *might* be exempt from this, but if you have playables for those functions (family members perhaps), then I would *think* you just use the same mechanics as always to set their 'uniform'.
RMK - that sounds horrible. (Apart from that I have nice default archetypes overriding the Maxis ones). I wouldn't want to have my playables get borked like that!
BO if the uniforms are saved to lot files, then they would be pretty hard to find I would think?
And if we can't find it in SimPE ourselves, I don't imagine we'll be very successful in defining a BHAV that identifies them in-game, either.
The only option left to us, would be to find the code that stores the information just after we've selected the outfit. We might then be able to make the game store the information differently, but we would also have to determine which routines all USE that information, because those then ALSO need to be altered to find the stuff elsewhere from now on.