Apart from the captaincy selection Warney's XI is actually sensible. Presuming Maxie's absence from this round of the shield isn't related to injury the odds of him making the side are even longer. If you want Finch down the order then I think you're looking for a no.3 as Usman would stay opener with Renshaw. Given the bowlers are a lock if fit the top 7 could either be Usman, Renshaw, Ferguson, Finch, Head, Stoinis, Paine or Finch, Renshaw, Usman, Ferguson, Head, Stoinis, Paine.
You'd be a pretty wary buyer of Stoinis but if M Marsh can't bowl the overs required then he's preferred. Besides he doesn't bring any more technical deficiencies with the bat. If Ferguson doesn't take his chance would be looking for Lehmann instead. Anyway I'd like to lock in Renshaw, Usman, Finch, Head and Paine for the top 7 which means Stoinis and Ferguson will be competing with Lehmann, Hughes, Weatherald and Burns for the other two spots.
EDIT. I guess I can't rule out M Marsh or Labuschagne but not consider S Marsh.