Are those bats suppose to bite enemies or my own agents? In 1-st scenario I will run out of bats soon. In 2-nd scenario I will run out of agents.
Either works, but enemies are preferable. Bats are
very good at melee evasion (and thus also CQC), so an isolated melee-only enemy is ideal. There's lots of cultists running around with clubs and baseball bats, plus monsters.
If you can disarm two non-surrendering enemies, you can torture them (and possibly others) to death at the end of a mission in the name of
science bravery training. Bats are best there because of their wound/HP ratio. Not applicable in all missions, but still.
Anyway, if a bat bites everyone else (once you have sufficient armour) for minimal damage and a few days of bed rest, you can get a pretty much guaranteed +10 bravery per mission. If enemies line up for bat bites, all the better.
You can also use the same old 'sacrificial rookie' gameplay of old, except now it's against enemies
weaker than you and the rookies get bitten, not blown up.
Requires one of the non-tiny transport craft, of course.
Yes, I know and use it. But it is definitely not "ultimate". I actually had a suspicion about if it trains bravery at all...
You're not using enough of it, then. And there is no better method for bravery that I know. Healing is riskier, as you yourself said. Piloting specifically for bravery is an exercise in frustration. Just shoot off a cloud of pepper sprey a few times per mission and the odds stack up. Or you can concentrate on training a specific soldier like with nothing else. Getting 3 or 11 sprays in mission after mission is
much more viable than doing 3 (or 11) healings.
I am not saying all this is always viable or makes bravery training
easy, but these tools are a lot better than trying to go through dozens of 10% lotteries
for just one or two soldiers via piloting.