RE: Aircraft rolls with up elevator
If it slow rolls, it might have a warped wing. In a loop, the wing is pitched into a greater AOA to get the additional lift that offsets the centrifugal force that's going to load the airplane. And warps work more than they do at cruise.
BTW, how square are your ailerons? Did you have to click any trim into the sucker on it's maiden? Aileron trim works great for level cruise but becomes flaps in a loop. And one flap is down and the other is up.
If you've got a lot of aileron differential to trim for level flight, it might bite you in a loop or any pitch change. That's why precision aerobatics flyers don't like wings that take aileron offset to fly level. They usually find a twist to remove that gets the ailerons back equal. And the airplane flies everything better from then on.