I agree that the Scandinavian would be bad to play as black. I also agree that we should almost certainly not invite the Nimzo-Indian. The only time I'd consider inviting it is if at least 1 event has been started by that time. The Nimzo-Indian seems very risky, since we don't know if bishops or knights will be better when the events start.
For example against 1. d4 Nf6 2. c4 e6 I'd suggest 3. Nf3 instead of 3. Nc3.
I think we should go d4.