Two style pumps housings - vent wise. Early style used a metal shield inside and attached to the support with two of the bolts - the shield covered the actual vent passage on the inside while another metal shield was used on the converter side and attached using two of the pump to case bolts.

Later design used a plastic whistle on the inside held in place with a "nail" ( not your normal wood nail but that's what they were called ). No shield on the bell side. If you are using the early style make sure you have that tin shield on the inside.

You mention leaks in neutral - how about in drive but not moving ? Everything is stationary inside in d or r if the car is stationary. If it leaks then you likely have something more serious going on.

One other thing to look for if you take it apart again - the pump bore where the pump fits the case - check at 6 o'clock - sometimes the soft plugs in the perimeter of the pump housing can get pushed out and when the pump was removed it left deep scratches in the case bore. This was more of a problem in the 2000 - 2005 time frame on 46/47/48 transmissions but something to be aware of. In some cases the soft plug fell out - this would cause a leak at certain times depending what circuit was affected.

All else fails refer to the earlier service manuals for checking for leaks using air pressure.
We check all our Reman transmission using Uson air decay - you can do the same basic test using air pressure and snoop - soapy water sprayed on the pump to case joint and bolts, front band pivot shaft plug and the converter impeller hub.