[notMyScreenName]

I'm not really familiar with the early cars electrical but most of those look like they are for the radio, and the one with the inline fuse (D) looks aftermarket. I don't think there were ever any inline fuses used on any of these cars (definitely not on the late cars). B and C are almost surely speaker connectors and the one below C in the first picture is the antenna.

Also, if it any help, on the late cars the tach is driven by the DME and the speedometer by a sensor on the transaxle. Other than power and ground the tach and speedometer are electrically unrelated. I'm almost certain that it's the same on the early cars but if I get a chance I'll check the diagram for the early 944 and confirm/correct this post as appropriate.

Edit to add: as h20cooled7 says below, on the early cars the speedometer is cable driven.