Genghis
I don't agree with your thread.
1) Whether or not the TCDS is part of the basis for issue of the C of A, the C of A, once issued, incorporates only the AFM, not the TCDS. Limitations are in the Limitations section of the AFM.
2) Your TCDS talks about requirements for certification, not for operation. FAR 91.213 does not apply to G-reg aircraft.
3) It's not reasonable to expect an aircraft to be operated in accordance with a document that is not available (note, BTW, that the incorporated certification basis is CAR 3 from 1956, not the 14 CFR that is the current FAR set. 23.1303 doesn't get a mention).
I think the references to the POH are closer to the mark. I don't have a PA28 AFM, but I do have Mooney M20J and PA30 AFMs. Neither offer a list of mandatory equipment. Section 6 is the weight and balance section in the M20J one, and it does have an "equipment list" that consists of engine, radiator, prop and governor. It has only an "X if installed" column. I can't argue with what's in your PA28 AFM, and if it says that certain instruments are mandatory, then they are. But it does seem strange that there such inconsistencies between types.
I would assert that the minimum equipment for flight is governed by Articles 14/15 (incorporating Schedules 4/5), Art 43(b)/(c) and where relevant Art 31 (Ops Manual for PT).
I'm not 100% that my interpretation is correct. Shall we ask A&C?