As for question 1....the 61fx will probably be plenty for the plane BUT...power to weight ratio is really a critical factor on this airplane. You would be much better off with a Saito .72. One thing you really dont want on this plane is to end up weighing in much above 5#.
Question 2......The carbon fiber rods...or some type of flying wire (again there's that weight thing) must be used to stiffen the horizontal stab. Be sure on the carbon rods to get them installed and glued well or they could be a problem.

If you go with a .72 Saito use the 13 or 14x 4W APC prop so you dont overspeed the plane.
If you want to do 3D with the plane pull back the covering on the trailing edge of the horizontal stab and leading edge of the elevetor and V both before hinging elevator. Iron the covering back down and trim if necessary. You really do need that much elevator. Check straightness of all tail surfaces and ailerons.
With this setup it is a great flyer.