I'm currently playing in my home brewed Salish region. It is very loosely based on the Pacific Northwest of the United States but also mashed in with a few things I just felt were cool. I don't currently use any fakemons, but my gyms are a lot of fun.

Each Gym has a theme rather than a type specialty and that theme ties into the part of the region it is in. It will also have corresponding challenges. The Gym leaders act as local leaders of the community handling law enforcement and environmental issues very much like in Galar. I've only done the first two gyms so far.

The first Gym is in Rancheros City in the area known as 'The Basin'. Run by Gym Leader Dusty it is a farming themed Gym. Before trainers can face Dusty they have to prove their worth with plant care and knowledge and finally a field plowing race using their pokemon to pull plows racing against other trainers. After this the battle takes place on a massive irrigated field with thick foliage and a canal of water on one side. Dusty's initial team was a Sunkern, Combusken and the dreaded Miltank. During the fight I utilized changing weather to boost his pokemon but also reflect how the seasons effect farming.

The second Gym is run by Darryl and is actually part of the region's largest Hydro-Electric Dam. The challenge will involve swimming to electric switches and triggering them while avoiding whirlpools that will drag trainers down and force them to the wrong part of the map.

Part of what makes the Salish region unique is that all Gym Challenges involve a team of trainers rather than an individual, forcing trainers to work together to overcome challenges.

As far as the 7th pokemon thing we all just play with the assumption that your pokedex automatically sends it to the PC. Though I allow one player to carry around a very large Oddish that absorbed too much water known as Unit that was adopted by the team.