Uh -- guys, you are over-complicating the problem. This is NOT a tailless aircraft & flapperon deployment in a tailed aircraft normally increases the effective AOA --- UP pitch. However, in this particular case the pilot has overcompensated for the anticipated (correctly) pitch-up with too much elevator down-trim mixing.

Remove the elevator mixing & try again -- carefully & at a safe height. It will pitch up -- work from there.