Yeah, local independent. As in they'd broken with the scene they were a part of, got some college radio time and were starting to become a part of the festivals. Just not so sure that, given this is 1995 and they'd put out two more releases by then (way, way more successful) that they'd go back to music from 1989/1990 from them for the movie.
If Carol's wearing NIN merch - while NIN t-shirts probably existed in the PHM era, sure - it's pretty likely from something later after they'd broken big. Keep in mind NIN were one of the biggest alternative type bands in the world by '95. Chances are she probably found out about them later on than the first album, unless Carol's some real hardcore midwest-industrial-pop scene enthusiast type.
But yeah, agreed on the notion that they probably don't pay too particular attention to this stuff either. Just kinda figure if they're playing up the grungey thing they'd probably go with something both heavier/darker (and way more known/successful nationally & internationally) from Broken or The Downward Spiral, rather than the pissed-off-Michael-Jackson vibes from PHM. It's sort of the unicorn of Trent's albums anyway, really different & sort of before he'd nailed down his own sound. Just don't think they'd use it, cool as Head Like A Hole is.