I'll put together a battle summons plugin at some point. There will be three types of summons
1. actors - that you can control
2. enemies - that you must defeat
3. NPC battlers - basically anything else that might interact with battlers. Maybe some boulder in the middle of the road, or a tower that does AOE fire attack around it every turn so you should try to avoid it.
For the targeting rules, I'm planning to go with maybe a line-of-sight implementation, and then you could say
1. someone covers an entire column, which means you have to clear everything in one column first before you can make your way towards other columns. Maybe a tank that blocks all 4 rows.
2. they only cover their row, so maybe two have two tanks that each block 2 rows, and if you defeat one tank, you could then target the ones that are now exposed.
It will use the same concept as AOE region painting, and probably use the same shapes so you could basically re-use those AOE shapes for other purposes.