Hmmm.... multiple problems here.
ALWAYS use a dual band external router mounted in line-of-sight ie- 15 feet up is good.
I have numerous ipad based mixers and I love them, but in a festival situation I always use a digital console. It is so much faster than analog. In selecting and buss- from input to auxes to L/R, I have instant command of that single signal chain. Looking at compressors is SO much easier that going to the FOH rack, and turning knobs labelled 1-10, with one tiny meter. I have cut back soundcheck time by at least half. If it's a band I've worked before, I can cut it down much further. Also, a band can give me a drive with all their effects and aux routing on it. Most of the bands I work with give me a drive with Behringer/Midas, DiGiCo, Venue, and Yamaha formats on them.