That's true, but if whoever is catching gets hurt, you just swap whoever is at first to C and you still keep the DH. Could get away with it once in a while but you're right, not frequently.
Figured Lamb would be out there in LF. Would also have been fine with Vaughn in LF, Grandal at 1B (then he can C the day game tomorrow) and Collins behind the plate.
I'd probably line them up:
1. Anderson
2. Eaton
3. Moncada
4. Mercedes
5. Vaughn
6. Grandal
7. Lamb
8. Garcia
9. Madrigal