Through googling I came across some wild man over on steam playing Dirt with FFB issues and a dll error. He moved immpid.dll (not exactly my pid.dll issue, but oh well) from syswow64 to system32. This seemed to help his situation. Moving the pid.dll from the 64 bit to the 32 bit location did not help my situation. I did notice that the pid.dll error showing up in event viewer is from the system32 folder though, NOT the syswow64 folder. I have 64bit mame installed with the respective 64bit ffb.
Everyhing's working with:
Demul, Model 2, all Tekno games
It's not working with:
Supermodel3 (that's ok, the native FFB works fine), Flycast, and MAME
Other attempted shenanigans included installing the 32bit version of the plugin in MAME, then swapping just the mame64.dll into the folder, then combinations of these things with different pid.dll copies in different folders. At this point I have to throw my hands up. It's odd that it works so well with some things and not at all with others, hoping Boomslang comes to the rescue so I can finally play Virtua Racing properly!