I’d slightly disagree with putting mortgage comparisons too far down the list. Even during general research, financing assumptions can change what “affordable” means. You don’t need a full loan model yet, but note whether each comparison assumes cash or borrowing.
A practical starting sequence...
The lease expiry profile matters more than a generic annual vacancy number. A long occupied period followed by several empty months produces a different financing strain from smoothly averaging vacancy every year. Run a monthly scenario around lease end, including lost rent, maintenance while...
I would still start with APR, provided every lender has calculated it on a genuinely comparable basis. It gives you a quick way to identify which offers deserve a deeper calculation. After that, rebuild the costs using the same loan amount, term, LTV, fee treatment and comparison date. Otherwise...