Is it possible to order people or militia to dispose of corpses?
I've had quite a bit of skirmishes over the Drassen's mine and now certain areas of this map are covered in carpet of rotting corpses. It's so damn gross...

As you've perhaps discovered by now, they automatically disappear after a couple of days

Let the crows do their job.

On top crows are perfect to train your mercs in strength (iirc)! Try out ;)
I love this game :)

You can also use cows, though there are some rednecks who don't like it.

To pick up corpses and move them to a different spot,
e.g. so your spies have more space to move,
put a knife in main hand and hit RMB, then click on the tile with corpse,
select to pick up body in pop up menu.
Note that it may cause diseases if these are enabled in your game.

To remove corpses in sector asap, pile them up and throw a grenade on top.

To push str, go to a sector which allowx to fill canteens via [ctrl]+[.] menu,
pick up a corpse and other hvy stuff to get encumbrance > 350%,
now let merc run til he/she drops, drink from and fill canteen, repeat ....
For rp aspect perhaps select another merc as drill sergant who obseves the training.

The crows are best used for mrk training with throwing knifes/shuriken,
that will also increase dex, and agi/str at a lower degree.


p.s.
crows will fly away if they see a merc trowing knifes at other crows,
it helps to place 4 groups of 4 bodies close to and around a building,
then move your merc in a way so that 3 groups and other ones in attacked group cant see your merc.
Also pick up knifes/shuriken in sector inventory so you dont chase the remainig crows away.

Are you sure you have the right game? You can't refill canteens in Jagged Alliance II, or pick up corpses.

You can blow up corpses with grenades or explosives!

He is speaking about JA2 1.13 "mod". You can do all that (and a ton of other stuff) in that. Yes, after decades of continuous development that may be considered almost a different game.