[Question] Which of these combat systems should I use?

See, I have always wanted to make a monster taming, pokemon-like game, but I could never decide on how combat would work. Outside of battle, I would probably use either a voxel environment, overworld map with random events, or an ascii dwarf fortress like set up. For graphics, if I want to do something beyond static and/or ascii character stuff, I would probably use paper mario esque sprites. For combat itself, I have several issues, but here are a handful of ideas for what I could use:

1. Turnbased Tactics (ie Pokemon Conquest, Fire Emblem)
2. Turnbased Tactics v2: An idea I thought up, it would be a 3d, voxel powered version where the tactical grid lines up with the voxel blocks. Monsters could even fly in mid air, in accordance with the 3d grid.
3. DOTA Style Combat: (ie League of Legends, Pokemon Unite) Point and click movement and targeting, top down graphics
4. Turnbased Tactics v3 (Sidescrolling version, think worms and other games like it)
5. Side Scrolling Fighter (ie Smash Bros)
6. Megaman Battle Network Style
7. Megaman Battle Network + Turnbased Tactics (An idea I came up with where it starts out as turnbased tactics, but when two monsters get close enough to eachother, there will be a brief battle network style combat sequence)

My main two issues is I am unsure whether to allow monster tamers to have more than one monster out on the field at a time, and whether the game should have action or turn based combat.

this really depends..
what program are you using? RMXP, Unity?

what kind of game are you planning- a side scroller, or top-down view?
a dynamic "run to a monster and punch it"? or RPG system where 5 party members must cooperate to defeat a powerful "boss"?
does winning require a bit of strategy, or it's mostly "grind to win"
does it matter where you're standing, and what attack you choose next?

what are your programming skills? can you write a 3D battle engine? or two separate battle systems for option #7 ?
what are your artistic skills ? can you create 3D models, can you create sprites and tilesets, can you draw images for monsters and map backgrounds? can you animate well enough to make a fighting game?

overall, I'd say go with a side scroller - it's the easiert to program/ find graphics for. a Side Scrolling Fighter battle could fit with that.
or, if you prefer 3D games: maybe a top-down 8-direction map with a grid, and pokemon unite battle system - assuming you can make 3D art, and animate 1-2 attacks for each monster.