>1 pair underwear, worn. Can be rinsed at night while wearing long underwear bottoms. No more shirts than I can wear at one time (ie, maybe 1 SS, 1 LS, but no duplicates). 2 pairs of socks--1 worn, one drying. Choice of LS or SS is based on comfort and I may swap during the day.
>No deodorant--why bother? Washing: hands after toilet and before meals, always and carefully, with soap or sanitizer. Anything else: if there's a good lake or biggish stream, the weather's hot, and no problem with LNT, I might jump in because it feels good. NO SOAP, and would try to avoid contamination from DEET, sunscreen, etc.
>Favorite UL "item" to bring? The knowledge gleaned from this site and elsewhere + experience so that I can leave a lot of other things behind. (That's probably a lifelong work in progress). I also like my first MYOG alcohol stove--built three or four years ago, it's always worked perfectly, and it was the thing that introduced me to BPL-style thinking.
Good luck with your thru-hike. JMT is on my list for one-of-these-days.