Games are a great idea, and competitive is good too.
(Carmansunshine, I can nod with what you're saying about I-am-better-than-you, which is what I fear when I play competitive games, but kids are pretty good at being positive competitive. They get over loss/victory pretty quickly. But if there's a bully situtation in the group, I'd pull it straight away).
*L hang/tuck hang monkey walks challenge.
*One on high, one on low (face each other): in L (or hang for HB), have a ball bean bag between their ankles, and they have to pass it.
*Set up a station for cast ons onto a crash mat (from front support):
Firstly on a line on the floor, then floor bar to mat, etc.
*Have them work with a buddy to 'check' their doing it right, also takes up time

*Circuits are the best idea. Maybe use:
1) the LB for casts, forward Roll to L.
2) HB L hang hold, or walking across the bar changing direction and grips (overgrip, 1/2 turn to mixed, 1/2 turn opp direction etc).
3) strength on mat
4) floor bar (buddy)- hands on bar, in front support. They have to keep a flat back, and practice different leans, to get used to the of leaning their shoulders over the bar (so small walks with feet).
5) Anything else you can think of (with so few gymnasts you may not need it).
This circuit also doesn't need a coach in any one spot.
I love using laminated pieces of paper and a white board marker so I can write down each station (so kids don't pester me with what they need to do). I explain at the start, give them the numbers (and they also like ticking off their tasks) and off we go.