At least for the first few tournaments, I think it would be best to have as many stages allowed as possible. From there, we can see which ones (if any) need to be cut. I'd also say that hazards should be permanently off. For irl tournaments, switching between hazards being on and off is fine, but for online games you could turn on hazards and pick Smashville, but then your opponent picks Unova League and thanks to random selection, congrats now you have Reshiram lighting the entire stage on fire. And hazards off allows so many more stages to be picked soooooo yeah. Anyways for the stages:
- Battlefield (plus any Battlefield forms of other stages)
- Final Destination (plus any FD forms of other stages)
- Dream Land 64
- Yoshi's Story
- Fountain of Dreams
- Pokemon Stadium 1 and 2
- Warioware Inc.
- Yoshi's Island
- Smashville
- Town & City
- Unova Pokemon League
- Kalos Pokemon League
- Midgar
And the next few idk since again I don't have the game yet and I haven't seen how these stages work out, but just to consider:
- Brinstar
- Delfino Plaza (I think it still travels with hazards off? so prob not. Same with other traveling stages like Wuhu Island and Skyloft)
- Norfair
- Frigate Orpheon (this section is pretty much just the Metroid stages)
- Halberd
- Castle Siege
- Arena Ferox
- Pictochat 2 (isn't it just Final Destination but with the slightly dipped edges?)
- Umbra Clock Tower
Either way please just don't limit the stage selection to Battlefield and FD. For this first tournament it's fine since everyone is still trying to get a feel for the game, but for later ones it absolutely has to include more stages. Maybe not as many as what I listed, but we need more than 2 options.