I'm a fool... Just did a smell test with renewed context and all but one of my snake enclosures smells of plastic (the only one who doesn't is the BP despite also having the same type of decor, his enclosure has a more natural earthy smell). Clearly I needed to do more than just a rinse to clean them before use and now I'm worried I've done irreversible harm to my babies...
I've promptly removed all the fake foliage decor from the corn snake PVC and the VBB's QT tub, and I'll have to effectively tear down most of the permanent VBB enclosure and get everything washed and soaked in a hot water vinegar solution. After all the work and money I've put into things and I still made a grave mistake, sigh...