Hey so I'm prepping a campaign and I wanted to implement the Knights abilities for my PC's but not design custom classes for each order. My whole plan is that the players don't pick their order, the spren choose them. I was just wondering the best way to go about it. Any advice?
An aerokinetist can do a pretty good job of imitating a windrunner. Use the electric kinetic blade to imitate a shard blade blade. Take the talent that lets you summon a small elemental to represent the spren.
A light Weaver is almost certainly some type of mesmerist
If it's not by player choice, and you're picking the order and the timing and everything, I'd just write up the abilities, have them given out as story bonuses, and not tie it to anything like levels or feats or any other player choice.