New Investor- Multifamily Contract Questions

[Crystal Ward]

Hello BP Family!

I am new here and new to real estate investing as well. I am preparing to make an offer on an apartment building and have a couple of questions. 

* Is it okay to ask seller to replace the roof (approx 20k) and ceilings, which he already knows is a problem?

* What is the standard Financing Contingency, Appraisal and Inspection, Due Diligence length? 

* Rent roll and leases etc.- should I ask for these in the special stips?

* How many days do I give seller to deliver copies of documents?

* Any other information recommended would be greatly appreciated.

Thanks!