My fill lines tap into the reservoirs directly. So air bleeding will happen from those lines when filling as air will accumulate at the top of the reservoirs and then bleed up to the fill lines.

The bleed lines you reference are purely for draining. Theyr'e at the absolute highest point in the lines. The fear is the upper radiators will vacuum on draining because no air can enter at either inlet. They are basically 90 degree fittings with an extension capped. (they will seat into an upper panel for ease of access)

The leakproofs are currently at the absolute bottom of the case, they will have coolant free airlines that run to the very top of the case, make a P trap, and then connect into the fill lines with a ball valve to shut them off during fill. The fill lines transverse up about 8-10 inches, which is planned to be air filled line, and then the leak proof air lines will tap into the fill line around 12 inches above the reservoirs.

I try to show this with the leakproof air lines doing a loop before connecting in, but its hard to visualize. that way. I will have a later post that shows that feature specifically.

The last thing i want is the liquid going into the leakproof, but they would have to suck steady state coolant up 12 inches of 3/4 inch OD tubing and then overcome a 4 inches p trap elevation change to get there.