Regarding Ranged Weapons, Don't worry Just make the presumption that these thing won't affect the characters on the same tile, unless it is supposed to like a heal cloud or something. Typically it seems reasonable that a bowman would not shoot the back of the people in front, but would shoot around them. Typically, all Tile Locked games, like Bards Tale 1/2/3 and Dungion Master 1/2 made the presumption that back characters on the tile did not injur the front characters when they shot ranged weapons.
If you are talking about something larger, like a stream of fire, or a cloud effect, you could make the same presumption. But if not, then put limitations that characters cannot use those types of skills if it will cause injury to their own team. (this works out, because sometimes you are attacked from multiple directions, and then those skills can be used without damaging the team by taking on the rear attacking force, or a side attackign force.
I might make it so ranged attacks/spells cannot be used on people in the same tile. Archers can switch to swords, Mages have close ranged spells (e.g. "burning hands" from D&D). For large effects (e.g. "cloud kill" from D&D) I could either make it not hit friendlies like you suggested, or have versions (e.g. "Fireball" from D&D) that damages everyone in the room regardless. Could be interesting design space.
Thanks for the discussion!
I'm wondering what fun I would have as a character on the back of the tile? I would not get to choose the tile to move, and would only be able to react during battle. I.e. which spell should I choose? which weapon should I use? etc... Unless I had a bit more to do, I would be annoyed playing an RPG (ROLE Playing Game) where my character moved on their own, and I only decided what to shoot with.
If every human player was able to move the tile that would be interesting, but could make things confusing, as one player close to dying might choose to move left, while another tries to move right, and then you wasted move speed, but are now back in the same battle you started in.
A map might be made up of 5x5 identical squares (25 square "tiles). Each player control only 1 character. This character can move from square to square with the arrow keys. When 2+ players all move onto the same tile, the icon shrink like in the picture I quoted in my original post.
So essentially its a typical standard tiled based RPG, with each player controlling just 1 character. Except that we allow multiple players to occupy the same tile.