I can't help you much on your questions about the engine or prop. I fly my freestyle with a Magnum .75 on it. It has plenty of power to hover and lots left over to pull it out of the hover. I wold imagine a .46FX will hover it but you won't have a lot left over to accerlerate out of it. As for the prop, I have no clue for a .46. Mine also balanced out fine with the servos in the stock location and the .75 out front. You may be slightly tail heavy with just a .46. Add a little weight to balance it where the plans say and then as you get comfortable with it start removing the weight and have fun.

It will knife edge great as long as you have enough servo on the rudder. I can get mine to knife edge at a high speed across the field and low angle of attack on the knife edge, or I can do a lsow knife edge at a high angle of attack where it is kind of a hover sliding sideways.

I really enjoy mine. Good luck with yours.