This is for people that I live with.
I don’t mean any lame team building exercises, but casual group activities. It could be something mundane like organizing a trip to the store together. Movie trips would also be fine as would showing something on the home projector, though I feel like there’d be more distractions and temptation at home.
Unfortunately it’s hard to really weigh in without knowing the individuals. There are alot of factors. A hypersensory person with autism would be completely different from a hyposensory person with autism. And that’s just one factor that would make a huge difference. You might have to involve them in any plans to find out what is a no-go for each of them.
But with that in mind, knowing that any one of these could be immediately shot down: Arcades, Bowling, Zoo/Aquarium, Go-Karts. For cheaper stuff; visiting a pet store, seasonal local festival/event type stuff, a group bike ride on a park trail. Stuff that really depends on personalities and interests but gonna suggest them anyway as it might not be something a normal person would think of; the type of party that highschoolers would have thrown back in their day(junk food, music, party games), a drive out to a local train crossing when a train is scheduled to cross(depending on interest level).
In my experience VR is currently much more popular among the Autistic crowd, so if you can either go to a VR arcade, or have access to a VR headset. That might be something to ask about.
But yeah, ultimately, it’s really hard to know as we’re all largely completely different. The few “commonalities” aren’t pervasive, just more likely.
I have two headsets but I’m not sure how many games are compatible between the two platforms. Anything with crossplay between the Quest and Steam should work.
High school type parties of video games and junk food can be fun but they can also be underwhelming.