Seems VIMs can no longer be used in polymorphic VIs either.
I don't think this is a good idea. The VIMs I've played around with (before the type case structure was introduced) relied on at least one terminal having a type which would dictate the undefined types due to the nature of the internal polymorphic VIs (like a Queue or DVR). This is why I was trying to get a VIM to create a DVR which "should" define the type across all connected VIs which would solve this problem. In a nutshell, I'm expecting this set of VIMs (rightly or wrongly) to behave like the Queue, Notifier et. al. primitives when the Enqueue and Dequeue element terminal is unwired.