Sunbringer

I don't know what I think about all these theories, but I don't think that the ghostbloods are bad guys. For one, they seem to be asking shallan only to do things that team radiant would want to happen anyway (besides recruiting an unmade for them) and if kelsier would join them, their goals can't be to nefarious, can they? I definitely agree that they wouldn't get along with Hoid, though. He really needs to get some better allies.

I think the Edgedancers would be the best at this. First of all, if you one really wanted to, they could slick the entire ground, making it extremely hard to fight them without the gravitation surge. The second point is the fact that they can actually heal themselves and others from shardblade wounds, which would make it very hard to keep them down. Their surges also don't seem to require very much stormlight.