Help Estimate Rehab/Deal Analysis

[Scheherazarde Roddie]

Hi, 

How do I give an estimate to a seller if I can't get a contractor out within a certain timeframe and I don't have the exact measurements for certain things? 

Current issues: 

- potential roof penetration

-plumbing do to leaks 

-cabinets (there was a leak under the sink and 3 drawers aren't working, do I price for a new set of cabinets?)

-HVAC generating air but the refrigerate lines aren't insulated and the temperature took 45 mins to drop inside

- 2 dead outlets and 2 outside won't take a reset

-need a hot water tank and the floor leveled where the hot water tank is (utility closet)

- two new decks due to mold spread

I plan to make a few calls this morning to contractors but trying to determine what other steps I could be taking to give to seller. They are willing to credit, but I'm thinking about the things I may discover during rehab after the deal is closed on. 

Thanks.