I dont disagree ith you about the winner (actually i don't agree either, i have no idea yet :P), however i can't see why you're thinking Laxu would only have a mid-high diff. The difficulty for either side would be extreme imo. Could you please develop your thoughts? =)
For me, I'm just comparing their battles with the Spriggans.
Even though Red Lightning was kinda BS, Laxus did pretty well in terms of endurance. Yes, he screwed up when he challenged Wahl, and yes, he was pretty much saved by Freed and Yuriy indirectly...
But his performance against an opponent who is immune to lightning was pretty damn good. Not to mention, Laxus was also sick and was at a disadvantage.
In addition, Laxus' nuke would have oneshotted and killed Ajeel. I've argued this in the past and I still stand by it. August blocked the lightning bolt because if he didn't, Ajeel would have died.
As for Jellal, I never found his feats that impressive. He used Sema on a group of Pre-Timeskip OS members and didn't even inflict major injury.
He inflicted moderate injuries at most.
Also, his feats against Neinhart weren't that impressive either. 1 year later, he used a more powerful Grand Chariot spell, and it only defeated Neinhart who doesn't have good skill or durability.