Geos attacked my g12 jawa scavenger before any of my g11 jawas

The only way to make that team work reliably is to make your Engineer fast enough to TM boost the rest before the Geos move, so Scavenger can get into stealth. Otherwise it's always a roll of the dice that your scavenger just gets waxed right away.

Do yourself a favor and find a better Geo counter though. Even if you win with Jawas it's likely to be a messy, low-banner victory.