Good choice with the Hasbro figures. Sounds like it will be an awesome display when you are done.
For my rooftop display, I did use the DST figures for the most part, since I have the Mattel and Hasbro figure in a different display and I wanted all the figures in the diorama to scale relatively well to each other.
Below is a picture from 2021. Slimer is now suspended with fish wire from the pillar above Winston's head now, since the stand broke (leaving the peg embedded). Gozer and the Terror Dogs are NECA. I swapped the proton streams out with Hasbro versions, much nicer looking, though I had to feed in some stiff wires to keep them from sagging.