> APIs, ABIs (which is super important for drivers)
Yes, only userspace code would be reusable with a linux based kernel. Might as well start from scratch.
One more option that's being tried is to split the difference by integrating more of Wine's code. This approach is being testing in the Arwinss branch[1]
> and possibly write a Linux kernel module that provided a NT-compatible driver ABI
NDISwrapper, Captive NTFS, Linuxant? Sure none of them implement(s|ed) the whole interface, but it shows that it is far from an impossible task.
Short answer: Yes.
Medium answer: That would be a near-complete rewrite of the project, since the ReactOS kernel and Linux have nothing in common. Different architectures, code styles, conventions, APIs, ABIs (which is super important for drivers). Probably the best option would be to port all of the ReactOS userland to run on WINE (which would actually be cool, and might be easy), and possibly write a Linux kernel module that provided a NT-compatible driver ABI (which would probably be hell to write, but if it's even possible then it would be a huge boon to Linux hardware compatibility... probably).