Lockers, only available 96-00
Full Time 4wd and TRAC/VSC standard on all 01/ 02, minus 1st option on 2wd models of course.
Tow package - very common, most 4Runners will have a hitch. There is really no more to it than a hitch and wiring on 3rd gens so adding one shouldn't be a big issue.
Sport seats, really no different than the SR5 buckets w/ lumbar control, the sport seats seem to have a little more side bolstering. I had the leather from a limited in my 00 and now I have an 02 Sport and the seats are pretty much equal, though the base buckets w/o lumbar suck and should be avoided.
Sunroof hit or miss on this one. Assuming you don't mind an auto you may want to look for an earlier limited model, most of those in my area have both the locker and sunroof. I believe it was 99 they started putting the full time 4wd system into Limited models. Also a Highlander package would probably fit the bill as well, those are the original Sport models before they called them Sport. That way you get the cool hood scoop as well.