4. Do you perhaps have, or know of, any other VEPro AU2 multiport workarounds that work properly in Logic 10.7.2's Environment?
Without seeing your actual project or a more exact and thorough description of the environment problem you're having, I can only point you to this 4 year old thread that explains one particular bug in the Environment that has existed for years and was directly affecting the VSL AU2 multiport macro templates:
https://www.logicprohelp.com/forum/viewtopic.php?f=1&t=137162
since you seem to have experienced a problem since updating to LogicPro 10.7, this may or may not be the problem you are experience, but it's still perhaps a useful example of a problem in the environment, with a possible work around. In this particular case the problem encountered 4 years ago was related to the fact that some transforms were not handling NoteOff events quite right...and even worse the behavior was inconsistent depending on whether the midi was coming from a region or coming from a midi keyboard. There are some really old forum posts, 10+ years, on the logicPro forum which also explain this particular problem and some work arounds, so it is not a new problem at all.
This work around eliminated many hanging notes that were common with the original VSL AU2 multiport macro templates.
I still rather recommend running the AU3 plugin on LogicPro 10.6.3 for now.
another problem with the AU2 multiport macro templates from VSL is related to what happens when you hit STOP on the transport. LogicPro normally sends out an All Notes Off message, which covers all 16 midi channels, to cut off hanging notes, etc. Unfortunately LogicPro does not encode those with CC99 messages according to the multiport macro approach, so you can be left with a lot of hanging notes when you hit STOP from that. My "snake oil" templates from 4 years ago included a Scripter script which attempts to duplicate ALL NOTES OFF to all the various ports, encoded with CC99, etc. It basically works ok most of the time.
Another problem generally noted by the AU2 CC99 trick is that it appears to create midi bottleneck congestion in LogicPro more often since so many midi events are funneling through a single process buffer. Setting the process buffer to LARGE does help. But another factor to be concerned about with this CC99 approach is that the exact ordering of all the midi events has to be preserved and there are some semi-rare situations where the merging of all the various tracks of midi into a single place...with CC99's inserted in front of Notes, etc..might sometimes result in two CC99's in front of two notes...instead of CC99-note-cc99-note..etc. which again, can result in incorrect handling.
Perhaps you can use the snake oil to learn something and repair whatever is going on with your environment setup that you are preparing to sell, which undoubtedly must be much more complex. The last version of the snake oil templates are here: https://www.logicprohelp.com/forum/viewtopic.php?f=9&t=137085
In general I still have to recommend NOT using the AU2 CC99 trick to handle multiport with vePro7. The AU3 capability works much much much better...with no issues at all related to NoteOff's and no environment trickery. The only catch for now, is that apparently Apple broke AU3 port handling in version 10.7, so stick with LogicPro 10.6 for now until further notice.