It's not clear from what you've offered so far but, you have a container of fuel, a hose from that to an inline filter, from that filter directly into the lift pump on the side of the IP, there is a good hose from the lift pump outlet to the filter stand's inlet (the fitting furthest to the drivers side), then a good hose from the center outlet fitting on the filter stand to the IP inlet located on the driver's side of the IP, then a hose from the passenger side of the IP retern/outlet to the return fitting on the filter stand (furthest to the passenger's side, correct so far?

If your container of fuel you are drawing from and returning to is too small you willget bubbles from the return fuel if that hose doesn't empty below the surface, and if that happens you will get air bing sucked into the fuel being fed to the lift pump.

Anything down stream of the lift pump should leak fuel if a connection is not tight it will not ingress air because that part of the fuel system is under pressure. Any connection before the lift pump which is noy tight will allow air ingress which you can see in the inline filter if it happens before that or if the line exiting the lift pump is clear you can see bubbles in that.

Of course the correct lines along with the correct crush washers are eventually needed but fuel leaking out isn't as much a problem as air getting into the system at this point.

If you fill the secondary cannister filter before starting to attempt to bleed the fuel system you will make everything easier of course.

If you have an electric fuel pump moving fuel out of the container and creating positive pressure you should be able to fill and move air out of the system delivering to the IP pretty easily and straight forward. I don't understand how or why but perhaps the electric fuel pump pressure is interfereing with the lift pump operation somehow, to eliminate that possibility just use a section of hose and no electric pump from your fuel container.