Does Red Hat ship (and maintain) arbitrary 3rd party code?
I don't know what you mean by "arbitrary", though. It makes no sense in context, and is notably at odds with your earlier use of the word "curated". Nobody ships random code. That wouldn't be curated, nor would it be useful.
Second is that I worry that bugs won't get filled against the original repos for people using your version.
Finally, I'd be worried about your version of packages drifting away from the original due to change in one or the other that the other party doesn't agree with. And then as a package author, it reflects badly on my project if your version of my library breaks, even if it's not my fault.
Import paths are not the appropriate method of providing "credit". That's the sort of thing that is handled by copyright notices, documentation, and metadata.
It's generally preferred that if you're using a software distribution, you either test bugs against a "pure" upstream version before reporting them, or report them to the maintainers of the distribution, who can triage and, when appropriate, forward bug reports upstream (possibly with patches).