Phipsl9

Also, since you have to wait a long time for your mega-charizard, it will be very weak and won't be able to provide sun for your chlorophyll venusaur. Consider getting a ninetales, so your venusaur can sweep more easily. Stealth rocks or spikes would be nice to have also imo

Not necessarily. I only ever used 6 mons when playing Reborn, cause that's how I always played pokemon. You can totally make it work, but the Kanto starters aren't that strong pre-mega, so stuff like Garchomp isn't a bad idea lol. I feel like Umbreon works on many teams, because it can toxic stall most difficult matchups, which your other teammembers can't deal with.

Hidden abilities are treated as regular abilities in Reborn. This means you can also use ability capsules on your mons to get HAs.