Captains, Gentlemen, and Flight Simmers etc..
It seems to me that the roll to inverted was caused by asymmetric lift, not asymmetric power.
Asymmetric lift caused by digging the stbd wing extension in the dirt and severely damaging it, or breaking it off. Ref several posts about Metroliner wing structure. Bearing in mind at the same time, GA power was applied together with high alpha. Almost perfect scenario for a snap roll.
Side comment. I find the Irish press reports refreshingly void of sensationalism, and for once, a much better source of information than my beloved Pprune.
Now running for cover.