Grizzly... yes as far the air bubble is still on the line it can return by the returning pedal action, including the hose to the recipient. But once the air bubble is out of the line it won't return no matter if is above or below the bleeder ( just like the ohms law on electricity ) Air won't retunr to the full line because the MC gets easier to get filled by its bowl than get back all the fluid from the line with its air bubbles and the hose is sunk,. That is pumping the system with the recipient,. Some air will return as far is on the line but keeping the pumping action several times with hose into brake fluid will eventually expel the air no matter where is the recipient.

Now about the gravity ( actually together with athmospheric pressure ). The recipient is still below the MC bowls, so no matter if the hose/recipient is above or below the Caliper or rear cylinders. Gravity/athmospheric pressure will still push out the bubble because MC bowl is still above the full system.

it happens the same when you extracts gas from your tank, once the line goes below the actual gas tank level, the gas will flow alone no matter if goes up first or how many turns makes before the final recipient... Is an athmospheric pressure principle.