In my opinion its like this:
Entire team made up of people of expensive background, such as raiders, iirc raiders have both high melee and high ranged (or any other background that offers both). It is essentially that EVERY SINGLE person on your team has at least 2 talents in melee defense, preferably 3.
You arm every single person with a crossbow.
First line gets shields and one handed weapons (axes).
Second line gets 2 handed axes, i think they renamed them to long axes.
Every single person has an axe mastery.
Every single person uses a crossbow as primary weapon and either a 1 handed or a 2 handed axe as a secondary weapon.
Every single person has VERY high melee defense by the time they are done (or nearly done) leveling up.
Essentially this team allows you to do some things.
First of all since every person can fire crossbows, you get to dish out at least one, maybe 2 turns of bolts at any approaching enemies. Against most enemies it means you will have done some damage, and in some cases thinned out their ranks substantially. Against enemies that are practically immune to ranged damage (skellies, orc warriors etc) you instead switch to melee weapons right ahead.
Second, due to high melee defense on every single character (and in particular the frontliners who use shields), your brothers become EXTREMELY difficult to hit. So if you use a shield + 1 handed guy as a mean to lock down enemies and prevent them from moving, a.) your brother in contact with an enemy will only get hit rarely (so you can tank all you want) b.) those enemies that can push your brothers away like orc warriors wont really achieve much in doing so as even your second line 2 handed weapons brothers will also be difficult to hit. Plus every time an orc warrior is not hitting you, is one time youre definitely NOT getting hit + its fatigue being built up for that enemy.
Basically because of this my frontline axe+shield guys can solo kill an orc warrior on their own (even though i would never do this unless i had to) because an Orc Warrior will fail to hit them 95% of the time, and they will fatigue themselves out while my brother will keep doing 2 attacks every turn (due to 2 or 3 talents in melee defense you dont even have to use shield wall, theres no need).
Once you have such a team, that can easily handle Orc Warriors, you can pretty much do anything, with the only possible exception being enemies that cause fear effect. But when it comes to normal enemy types, they all become a non issue, you just apply regular tactics you would use otherwise (attack goblins at night etc).