Winter is coming and I have a beater with no heater... (89 740 GL Auto) California driven mostly but wants to visit some national parks in the snowy parts of the country.
I drove the car to Yosemite and the heated seats were clutch but I was shaking in the morning (talking about driving like a real man no ac no heater eh...)
So I wanted to put in a heater core that was previously disconnected by the old lady who had the car from new. I understand that this is a fairly involved process so if possible I do not want to repeat this process within another month just because something failed...

Any input is appreciated
My beater wagon in the wild


Therefore, I am turning to the seasoned experts in the forum to seek answers to these questions and ask what else I need replaced:

1. Has anyone had any experience with Four Seasons Heater Core on Rockauto? UAC? OSC? All seem to be aluminum construction with no plastic, with the only difference that some of them have seal on the outside. I do not need crazy heat as I do not daily the car in Alaska, factory brass is way out of my budget and a repair of the original is out of the question because this is my only car and I do not have a means of transport once I have it out. I would like to repair it and shelf it though for the future
2. What other components should I replace alongside this?
1) Thermostat, is stock 92 the best for NA?
2) Lower radiator hose (slow leak after flush)
3) Reservoir cap
4) Reservoir to radiator hose (slow leak, possibly the reservoir as well)
5) heater hoses? They are joined together when the heater core was bypassed and not leak, the aftermarket brand available is URO so I am a little suspicious
3. I am not sure how to check the heater blower motor although I recall it does blow air through the face vents but not on the feet vent (lower). Does AC share the same blower as the heater?

Finally, I am an engineering student getting through college so I do not have an unlimited budget to replace every single old hose but I do want to take care of the car little by little as the Volvo wagon is a reliable old friend who chugs along the road and gets me to where I needed to go.