Here's a link to the IRS website noting specific items that are included in the cost segregation study report on page 24.

You should communicate with the sponsor on expectations of when you plan to be getting the K-1's.This year was unique with partnerships as they wanted to know how to report specific items from tax reform.I think you should consult with a tax advisor once you have large investments.

Ok so why are you asking about these two very specific items? 

There may be some specific item you learn that proves valuable.

I need to get comfortable with macro items (location, demographics, etc) before LOI, then the bigger building specific items, (say the roof is falling apart, etc.) won't come out until we've agree on an LOI and I'm diligence....

I will echo some of the others here...yes and no.The trade specific items like plumbing parts and electric boxes etc...we don't buy.The design based items like toilets, LVP, cabinets...we buy.Not to save money per se...but we want to decide the look.

How did you all calculate the cost of specific items such as; window, doors, roof, HVAC, cabinets, etc?

There are standards of practice and specific items that they are required to address and note as deficient or missing. 

Before they moved out, I sent email twice on their lack of maintenance on the garden, and specific items that were totally lack of maintenance, upon which they never replied.

Then you can start asking questions that have you confused about specific items.