It's not easy to pick, but I think I'd go for something like this:
Marshall
Palmer Devlin McKenna Taylor
Armstrong Jack McGregor McGinn Christie
Naismith
1) No solid idea what shape to play those 5 midfielders in, but Jack sitting back and Christie in the hole behind Naismith would be a start.
2) I'm not convinced by Devlin, but given the options, starting McKenna's regular defensive partner