What could be a good or funny name for this party?: Honestly I like the idea of reusing Come Together Party. Just by reading it you already know what the party is for. However if you like any other name that's fitting for it, then by all means go for it! It's your party anyway~
Any minigame ideas?: Granted I never got to go to the first party cri it sounds like everyone loved that little game you had last time. It sounded really fun and I'm sure it was! So I don't see a reason not to use that minigame again but in a different map.
As for any other games, I'm not sure what to suggest. Hide and seek sounds like a great idea if everyone plays fair.
Should I try to make a discord server for this?: Honestly it's up to you and what you feel would be best! In my opinion I feel like discord is kinda taking away from the forum and what it's here for, but again, it's totally up to you and what you wish to do =)