Yes they are.

No. The only gift needed is your presence.

No. Alhamdulilah the Nikkah is already completed so there is no need for gifts for the Walimah.

This is a very good question, since some Guyanese people will take it literally. Yes, while you can wear a black tie, black tie attire means formal evening wear. Consisting of suits and floor-length dresses.

InshAllah, there will be flooring for the tent, so your feet shouldn't get wet