Marsh is probably the best number 3. I'd not risk Starc.
Smith averages 50 at 3 and only 30 at 4. Smarsh can bat where ever. Finch lucky he is captain otherwise I’d be opening with Warner and Ussie. Finch bashing a 3rd string pakistani lineup hasnt convinced me there isn’t still a bullseye on his front pad for good bowlers to target.