Thanks for the ping! This is not really relevant for marvin. Marvin’s main purpose is basically allocating (hu)manpower (can’t think of a non-gendered term right now), not merging anything.
I do think its a very promising idea though, I have proposed something similar in the past.
One potential issue with your suggested approach comes to mind: How do you handle things that currently go through staging? If you keep the staging branch, you would still need to serialize the merge back into master which could potentially block things that would go straight through master right now.