I think it is best to rent a VPS to less complicate since most of VPS are already open ports and you just have to configure IP's match on your VPS IP...
Setup the game via hamachi for testing purposes first then once you feel you can handle the game online then you can rent a VPS or DDS, (Hamachi) is...
sure, since after the event ends the settinggs that are applied are more correct than doing it manually, but mostly this shouldnt been an issue, its...
hmm... seems like a weird bug, i am not sure how to help, if u open to everyone u can join right ? and what about the guild members can they join or...