To buy
Antifreeze and distilled water or... coolant pre-mix (very handy) 2 gallons.
Freon, one can and an oil charge can.
Heater core.
I used 1/4 thick by 1/2" wide closed cell weatherstripping as the old stuff on the heater core was shot.
Lithium grease for the various damper hinge posts.
Tool-wise it was really basic and minimal other than a trim removal tool if you prefer one and the Freon line release tools.
The heater box screws REALLY liked to bind up going back in, so I wouldn't power tool them.
Pretty sure that was all. If I think of something else in the next day or two I'll post it.
The core I got from rockauto was made in China and had about 10% less fins than the French factory model, but fit perfectly and seemed a bit heavier and sturdier.
The hardest part was really the double nutted stud directly behind the head...that one!