I'd intend to get some nice candid shots, group photos, and individual portrait style pics if people want them.
of these things, only one will work out reasonably well. portaits.
iso 800 just isn't enough to take general pictures indoors without a flash. you'll need a very fast lens, like f/1.2, to even hope of a fast enough shutter speed to shoot handheld, and as a result, you will end up with razor thin depth of field.
so although portraits will look quite nice, group shots will end up with most of your subjects being somewhat out of focus, unless you use a slow shutter speed and a tripod to compensate for the tighter aperture. similarly, you might struggle to find the candid shots you want when your depth of field is about 5cm wide.
maybe pushing the film to 1600 may work out for you, if there's bright lights indoors, but you'll end up with high contrast shots and colour shifts. delta 3200 is my go-to film for indoors work without flash, but i'm ok with everything being black and white, grainy as fuck, and looking like it was shot at a punk gig
really, you can't do indoors with film without some sort of flash, and it's not that fun.
for candids, you'll likely end up spending your time adjusting the flash power for the subject distance. for group shots, unless you have a bounce flash with TTL measurement, you'll end up with washed out front fill flash photos where everyone kinda looks like a passport photo.
so my advice? give up on available light photography, get some decent colour film, and shoot with a flash, ideally one that uses TTL measurement so you don't waste time doing the power adjustment, and one with an angled head and a diffuser so people aren't lit like rabbits in the headlights. i mean, unless the vibe you're after is "a 90s disposable camera" in which case get the front fill flash. i've done it for precisely this reason.
then expect to be very unpopular because flash photos piss everyone off. guh.
anyway: as much as it sucks to hear, my advice is "shoot digital indoors, it handles low light way better", and i hate it.