Hi Mike,
first of all, thank you for your hard work in building PBY, the updates and answering all the questions... (and yes..I found the PinVol easter egg
)
Now, I did do some tests with V6 and ..well...there is some good news....(that was the positive note).
So...as I can not say directly, this and this is not going well I will tell you in detail what I did and what I see, may-be you can get a conclusion from that:
1st : I deleted all the contend in the D:\pinbally directory to have a fresh start.
Unzipped all the Alfa V6 / 64 to this dir and started PBY
Put all screens on it's place
Now, 1st I see is a very strange set of tables, some I recognize, some I don't and most of them missing all media.
When I check the box 'Unhide games....' in the Game Wheel menu make disappear the strange tables and only the VP9 tables remain. No clue however where the strange and unwanted tables come from though.
Now, only VP9 tables are visable, together with all media and (...!!) table sound!
But, no pin two-you-know dmd. When I enable it for sure in the options menu it gives an error that it can not find dmddevice.dll and that it should be in the \pinbally folder.
Did that but same result, no real display.
For the next story I fully disable the real dmd to see if I have on-screen dmd.
Enabeling the software on-screen dmd gives me a 'PinballY' display but it does not display the attracht mode display files. Just like the table sounds the display sounds are linked to each table to show up during the use of PBX. Same story as the table sounds.
Starting a table with a DMD display does blank the on-sreen DMD (so it's a black rectangle) but no display on the virtual DMD.
Also: the topper which was displaying a video during PBY stopped working (black screen) when starting a table.
When I exit the VP9 table the topper comes back as well as 'PinballY' on the virtual DMD.
Now....that was the VP9 part.
Now the VPX part:
No VPX tables are being shown by default. That is strange because the information is there.
First I made use of the new file pointing addition you made pointing the media and database folder :

Now....In these folders there are (a lot) of subfolders but also the subfolder called Visual Pinball (for the VP9 tables) and PinballX for that kind of tables.
Looked at any changed but...still no VPX tables.
Then I manually filled in the media and database folder into the 'systems' tab:

The Media folder is pointing to D:\program files\Visual Pinball\PinballX\Media\VPX and the same but ...\Databases\VPX for that.
Now....That gives me my VPX tables, including wheels, including table sounds and also Launch sounds when (trying to) startin a table. (but also, no virtual display).
But....starting a VPX table won't work :

If I make a wild guess: I do think a lot of the mentioned problems refer to 1 thing: not being able to locate the VPX directory.
You see it when running PBY initially : no VPX tables being displayed. You see it in the DMD movies/images: not displayed on the virtual dmd) and when starting a table: it can not find the specific table.
And then there is the Pin2-you-know error which is pretty strange as I did copy dmddevice.dll into the \pinbally root but we can adres that later.
Now...that's it for me for V6 so far....again, thank you for your hard work :-) !