No........and yes.
The only way to advance any league is if ALL spots (in your case all 10) have user owners to start the league.
Sounds like you are two spots short. You have a couple options to fill those two spots to be able to advance your league. One option to to have to buddies join your league with the understanding you will drop them immediately after they join. You can tell them which teams to pick. Once they have joined and have you have dropped them their teams will list as CPU teams and you can advance your league. Also, the two guys you are waiting on can jump in with their league invites and grap those two teams. I would be glad to accept one (maybe both invites - one for each system) and then you can drop me.
Your other option (which is a bit of a hassle) is to create two new gamertags for your system. It basically is a process of getting a new email to get you going. Once you have two new gamertags you basically invite yourself twice and dump yourself twice.
Hope this helps.
S