Starting out I’ve found that equipping your starting brothers as well as you can is the best bet. I’ve had good luck with spears and shields at the start. Your Brother’s melee skill is extremely low at the start, and while big damage is sexy, being able to hit enemies and overwhelm them is important in the beginning. As far as armor goes, I’ve found spending the majority of your starting money getting your starting brothers well equipped. This means buy up the aketon, or the mail shirt if available. Grab whatever low end helmets are available. After that’s all settled grab the lowest cost merc available. Lean towards Daytalers and Farmhands and hope your new Brother’s aren’t dodgey as far as perks.
Always friendly. From what I’ve gathered these are what determine what equipment is available in towns so even if you could pillage them you would be shooting yourself in the foot. Although playing the heel would be fun.
Like Malthus said you can’t take them over or build them. It would be excellent if you could grab land and transform from a minor military band into a full fledged power in the region.
Again like Malthus mentioned avoiding orcs is best until you have a full band that’s both experienced and well equipped. Some Orc Young can be fought relatively early if you have a few experienced (4-5 level 2-4) Brothers and some spears. Keep your Brothers close enough to support each other when they inevitably get charged. Use of Shieldwall + Spearwall perks can give you free damage on charging Orcs. Or keep them out entirely if you’re lucky on rolls. Once they’re in, I’ve relied heavily on spears and overwhelm bonus. Impale them with a spearman, then have a heavier hitting Brother (one with an axe, sword, or two handed weapon) come in to lay on the pain. Also, if you figure out the positioning, you can engage on an Orc before he even charges, normally this means you’re in his face without an attack or shieldwall on, but you aren’t stunned either. Only do that if you’re confident your Brother can take a hit though.
Have fun experimenting with them and find out what works for you though.
PS Withered Vampires are literally hellspawn.