Okay Multi Battle info I've just figured out if anyone is interested
I scouted Wally. In singles he Lead with Mega Garchomp, then Altaria, then Magnezone. It really surprised me he had Mega Garchomp. Does anyone know if Cynthia also leads with Mega chomp?
So in Multi Battle He again goes with Mega Chomp, followed by Altaria. Both with Mega Stones. But again he always has been leading Garchomp (been leaving and returning after every battle, trying to get him to switch lead mons like in ORAS, but no dice after 5 tries.) I will say Wally Chomp has a beastly 244 attack plus sandforce which can be nice.
Other thing I've been trying to figure out is what determines the two pokemon you get from the trainer you scout. I was thinking it was just whichever first two you encounter in the battle, since signature mons of characters weren't being picked and thats what I was getting after scouting 4 of the 10th battle leaders (or whatever they're called). But then I tried scouting a random one, Verna. In super singles she went Lapras -> Feraligatr -> Politoed, But rather than getting Feraligatr as her multi battle backup, she has Politoed. This would suggest the opposite, that there is a guaranteed team you get from whoever you scout, and for Wally that appears to Garchomp/Altaria rather than Gallade/Magnezone.
Screenshot of summary stats on Wally here:
http://i.imgur.com/yuU58if.jpg
Also, as far as I can tell you can only have a scouted AI, or an infrared-linked friend as partner. No Friend AI like in XY or Wi-Fi partners as far as I can tell, unless someone has found something I haven't?