operating under Part 91K, Part 125 and Part 135.
So therefore this course is not required for a ferry pilot legally, as ferrying is none of the above. A nicety, maybe.
Also, P-RNAV probably won't be required as no puddle jumper has this capability. Many jets don't. B-RNAV seems the only relevant course. Let's not forget you need approvals, not just training, for P-RNAV, so a course on its own is worthless. As a ferry pilot, are you the holder of these approvals? P-RNAV I doubt it.
Also, if you say you need MNPS courses, you'd still need an approval to operate (LOA/Opspec under FAA etc) At NAT MNPS levels, you'd also need RVSM which you have not mentioned. All a bit unnecessary in my opinion for ferrying piston singles and twins. Worthwhile for TBM's, Malibus, JetProp DLX's and the like no doubt.