All three of Lolesio, Donaldson and Gordon will be in the squad. It's too early for Lynagh (and I say that as a Reds fan who rates him highly) and as others have mentioned Edmed isn't up to it and Harrison is going overseas and has only just come back from Injury. Personally I'd be starting Lolesio as I think he's been the most consistent 10 this season and his goal kicking ability is vital, and I'd be bringing Gordon off the bench. His goal kicking worries me but his ability to put players in space and attack the line could be a real weapon in the final 30 of a test match, plus as others have mentioned he can cover 12 and probably 15 at a pinch. I wouldn't hate it if Donaldson is given the 10 jersey, but for me it makes more sense to play him against Georgia and have him as backup if either Lolesio or Gordon get injured.
One bonus that I don't think has been brought up yet - White will definitely be either starting at 9 or will be on the bench. From a cohesion perspective, that's great for our young 10's considering how long he played with Lolesio at the Brumbies and how well his combination with Donaldson at the Force has gone this year.