Harry was of course there :D He forewent the 'traditional' coming of age presents he might have given back in the real world since he assumed Remus and Tonks would take care of that. Instead he gave Teddy a box of Filibuster's Fireworks with a warning to please not let them off inside the house no matter how safe they are.
Frankie came and ate food because he needs no invitation to take advantage of a free meal. He gave Teddy a Star Wars lego kit he got at Smuggled because he thought it was cool.
Peter didn't come, but he heard about the party on the grapevine and sent some of Remus' favourite chocolate on the assumption Teddy would like it too.