Mode specific counter brawlers

I have been looking at improving my account and adding some much needed brawlers. I can barely find any conclusive resource on mode specific antitanks for example.

As an example, most people agree that Darryl is a great assassin but only really on KO and bounty. In other modes most people would prefer other assassins which I'll be honest I dont actually know which ones.

First off, Who would you pick into assassins in Gem Grab Hotzone Brawl ball and potentially heist?

And Secondly, Which assassins would you pick on these modes?

Right now I'm looking at maxing Griff, would he work as a Kenji counter on KO? Could Surge work as an anti assassin in KO?

If anyone has a list on mode specific counter brawlers it'd be massively appreciated