1.5:1 thrust to weight is more than enough for a KE loop. You don't need 2:1, but 2:1 is nice. Anything more is silly unless you are doing extreme fun fly/ 3D. I think the problem is with your plane setup. You mention the plane barely does knife edge in post 5. You don't even need 1:1 power to hold KE, so there is something wrong with plane setup. Where is your CG? Throws? How much does the plane weigh? How much is it supposed to weigh?

As for elevator causing roll but no roll with right rudder business. Your initial post is confusing. I can't figure out what you are asking. Does your plane roll when you make pitch changes?