Having been in several S&R training days & nights and one S&R in NW Pennsylvania I have some opinions on the gear needed.

Search & rescue gear, like military gear, needs to be robust and utterly reliable. Dri-Ducks do NOT fall under that definition. Even under other clothing I doubt they would hold up to repeated use.

Mountaineering clothing and gear will do fine and can be used for winter camping. And, of course, new or good surplus military gear will work just fine.

Eric