Hi @JohnDel ,
If you just import the SDK2.11.0 demo, no issues, right?
And, if you use your customer demo, which update the SDK to the newest one, then you meet issues, right?
If this situation, I suggest you use the SDK2.11.0 demo as the base, then add your customer code again to the new SDK project, whether this method still have issues or not?
I import one new project with SDK2.11.0 with MCUXPRESSO 11.5.0, no compilies issues.

So, you need to check your installed SDK, do you update the SDK to the newest version?
About your suggest, it is determined by our SDK team plan of the detail component version.
The driver normally just add the related fsl_xxx.c/.h, to the pinmux, you need to use the periperal tool to add it, or add the code in the pinmux.c directly.
Or you can copy the related demo pinmux.c to your own project.
Wish it helps you!
Best Regardards,
Kerry