I was actually unaware that the illusion set up into SH Uair at kill percents, I think I'm gonna get a lot of mileage out of that.
Against opponents who aren't too eager to edge guard, or retreat across stage to use projectiles, I like to use illusion to stall at the edge and bait out an opportunity to approach. I grab the ledge, drop, quickly jump then illusion back to the ledge, repeating the cycle while I look for my opening. The difference in height between an illusion to the ledge and one that slides along the stage is very subtle, so once you have a handle on the spacing you can surprise your opponent with the on-stage illusion. Of course this strategy has a lot of weak points, good players will be able to react as soon as they see that you didn't snap to the ledge and have a punish ready, but it is still a viable option, and after you've repeated the ledge cycle a few times you can just use a different getup option if you don't think the illusion will land.