To turn captive soul into servant, you need like 65-72 subservience to you. Can do it with master obedience training, making them obedient. And then either doing some submission training, or hypnotizing them to subservience to you. Mantra works too, but it might come up problematic because mantras seem to be affecting certain perks constantly. Or just waiting out. Think of servants being like not good enough to be deemed residents who have certain rights and demands, but not rightless prisoners.
You can hover over the perks to see what they are. But really look at them as tags. Most of them do nothing unless they belong to soul perk. And even then you might need incarnate certain targets, or deincarnate to souls. But other than that, sharpshooter does nothing except some assignments which tell if it needs for example. Same with other skills so you do not really need to know what they are just what they do. Also look at class definitions in drop down menu, like 90% of class requirements are in the assignment. So if you pick role 1 saying something like scout, and other assignment has scout it would match most likely almost fully. Also would recommend copy templates from those and use whatever means to bring them closer. Though there are certain common things, like aggressors are better from corrupt races because of what traits you get by corrupting people or using certain cursed items. Defenders a bit more from purified races. But other than that you do not care what race you use. In most cases.
Effectively this game is one of remakes of no haven or fort of chains. Some things does better some feel redundant. But again it is far more convenient to play. Because it was a hell to try and figure out what classes did in no haven and what tags came from class and what were random. And with how limited those games were in changing things out it was hard to figure out. (no haven especially had that quirk no bad tags, so we have same kind of assignment having just random set of tags which hard to match.