Well after many exhausting hours of deliberation with wiring diagrams I looked again at the connections in the corner of the fender/bulkead near the heater box and noticed that there were two sets of block connectors that could be fit together even if they weren't supposed to go together, one wiring loom went out to the fuel tank I imagine and the other was for the heater blower motor. Both had purple wires which made them even more difficult to distinguish from one another. So I plugged them in properly by switching the block connections around and suddenly everything worked! Of course that was after I took the heater box out a second time in order to make sure I hadn't done something else wrong and to make sure there was nothing wrong with the blower motor itself.
With that sorted I put everything back in place and it was all downhill from there.
While I had the heater box out my dad helped me sand and respray the all of the parts and plates flat black. We also added some foam strips around one of the ventilation doors inside the box to ensure a more air tight seal.
The original thick foam gasket around the blower inlet that mates up to the plastic intake manifold had deteriorated long ago, so I used some generic black household plumbing insulation and made my own. Here are some pics from the refurb/refit process: