Please refer to your RSVP to see which events you are invited to. You can re-enter your name to check even if you have already RSVP'd.
Semi formal - be comfortable and ready to dance! You don't have to wear a tie if you don't want to.
If you have a plus one they will be named when you RSVP.
We absolutely do not expect gifts! Your presence is present enough, of course. However, if you really would like to get us something, we've put together a selection of things via the Wedding Present Company to show the sort of things that would be nice: https://www.weddingpresentco.com/find-list/241507