Ngl I still have no idea how to make money via combat, hired Ayden and almost went bankrupt because of his upkeep and the amount of medicine I have to buy/use everytime I fight. Please teach me da wae sensei
Ayden is almost always my first pick for a top tier merc. He does the most damage initially and comes with great skills and duraplate so he also makes a great tank.
What I do is pick up Ansel, Peasant, Loren, and Rifle Savant on day 1 to do a few easy quests and bounties. I avoid any difficult fights on day 1 because Rifle Savant dies if someone so much as sneezes in his general direction. He has great aim though.
Day 2 I replace Rifle Savant and Peasant with Dexter and Doyle. If I haven't found enough rifles yet I will swipe Peasant's and give it to Ansel. With that group you can take on some slightly harder fights since Doyle is pretty good and you don't have anyone with less than 75 health anymore.
Once I unlock Crystal Hills I replace Ansel with Ayden. Now you can do tier 4 bounties and the regular random arena fights no problem with Ayden tanking and 1 shotting the toughest opponents.
If you do a bounty every day you can start seeing the tier 5 bounties on day 15. If you had bad luck on them initially you might have had to skip a few (doing a tier 4 on day 1 is usually a bad idea). When I see my first tier 5 I go pick up the Blackguard, replacing Loren. If you pick Felix or Space Marine before those 2 you will need to also buy them duraplate, so I like to save them for later. Ayden and Blackguard already have it.
That carries me through to day 35 when the first tier 6 bounties can start showing up, at which point I pick up Felix and Space marine and run with a full squad of top tiers. You also want to read enough medical books to get your medical skill to 40 before then because you WILL be losing people even with 4 top tiers when you do those tier 6 bounties. Doctor's kits allow you to patch them up without stat losses.
Duraplate is expensive so initially I just get combat armor for myself and 1 suit of weave for my slaves so I can rotate them into the easier fights to build some respect. Caitlyn can fix combat armor for free if you make her your quartermaster. She requires further training to fix duraplate so I usually wait a while to buy that for myself, but I do buy it for all of the top tier mercs. I don't bother for the lower tier mercs.