Just saw the anime episode for the prelims. looking back knowing everything we know about the 8 teams that qualified, I think everything makes perfect sense:
#1. It's possible Minerva was around to teleport them... that aside, Rufus's magic lets him know the entire field and memorize it
#2. FT-B, well, between Jellal's heavenly meteor and Luxus's lightning, it should be a breeze
#3. Raven Tail: this one doesn't make sense considering they got OHKOed by Luxus later... but they needed to look strong as an FT arch-enemy, and their master was in the team so oh well lol
#4. Lamia Scale: Jura FTW!!! he probably made some extra stairs for his team
#5. Blue Pegasus: Hibiki (was it him?) and his archive magic. but they're not as strong as Sabertooth, hence 5th place
#6. Kagura and Rily knows gravity magic, should've been easy for them
#7. Quadro Puppy: well, they've all turned into fodder. All things considered they're replacable with any other fodder guild
#8. FT-A or Team Natsu: Plot armor FTW! enough said