I think the jigs being easier question depends on what instrument you play and what you're used to in your normal repertoire. I _hate_ jig rhythm on the guitar. The band the I played with was actually better-suited to square dances and used to playing mostly American midwestern fiddle and banjo tunes and dreaded being asked to play jigs. We could do it, but none of us liked it. We also didn't like being asked to play medleys, but that's common in contradancing and is more fun if you can coordinate it.

Our requirements were pretty standard 1) steady, audible rhythm (bass, piano, stomping, whatever it took), 2) not too insanely fast, since we had to keep it up forever, 3) we tried not to choose extremely intricate tunes because they tired our hands out faster [probably not a problem for more skilled musicians with healthier wrists]--sometimes the break was enough to refresh us and sometimes it wasn't, 4) the caller probably won't want you to play crooked tunes--they work OK for squares but I'm told they don't for contras.

But yes, our dancers have always been forgiving