Hmmm.... OK, Alright. I'll just do my idea burst then.
The typical advice is to "heel in" bareroot trees that can't be planted. Google search (or whatever) this and see what you think. I would adapt that technique for these trees. There must be a reason for keeping them at the 45Ã‚Â° angle. Remember to take care not to bend or disturb the taproot. provide PLENTY of root space. RBG's advice to put in protected location is a good one.
I think I would wrap the pot and "sticks" in burlap, perhaps stuffed with leaves or put straw around the little trunks first. Unused "so called" tomato cage (three legs and circular hoops) might provide a good support for the burlap.I would consider protecting with hardware cloth if mice or rodent is any kind of possibility. alternatively, bury in leaves/straw then cover with spare fencing.
I was also thinking refrigerator as a wild alternative if you're the sort of person to have empty shelves in the fridge. But it sounds like that won't be necessary.
I'm relieved to hear the seller is in Michigan. I realy think there must be different localized species because quite a while ago when I started even considering pawpaws, ALL catalogs I got, that offered them said "hardy to zone 6". More recently, within the last 7 or 8 years, there has been more hoopla about pawpaw as a desirable home garden item, and named cultivars, etc. started snowing up. Now they say Zone 5 or often even Zone 4. I'm still adjusting to the idea that pawpaws are cold hardy.... (though for people who liv in areas where pawpaw are native and "everywhere" this might be a strange notion