as far as im aware, yep! StreetPass works with other modded and vanilla consoles

I think it is for the most part! I saw someone say to open a non pirated software before closing your ds however, as others would be able to see it ^^

You can definitely use streetpass on a modded system, and on universal updater, you can install netpass, an application where you can streetpass people over the internet!

Im very sure that nothing can happen if you use StreetPass on a modded 3ds because i often use NetPass or just StreetPass with my second 3ds and it works fine