A quote with no cost breakdown can definitely be a red flag—it makes it harder to understand what you’re paying for and leaves room for unexpected costs to pop up.

For residential multifamily properties (1 - 4 units), can you use a home warranty to take care of the repair costs associated with rentals?

What I have seen in the research is to find a property you are interested in and compare to other comps in the same neighborhood.

However, I still struggle to understand the art of estimating rehab costs. 

@Landon Sheveland People do fix and flips while living into the property to classify the property as primary residence and not pay any capital gain taxes. if that is your intention, don't use LLC to establish this as your LLC.If your goal is different compared to what I said above, you can use LLC.

Does Hard Money typically cost 30-40% of the purchase price?? 

That cost me about $1,000 each time. 

For your $2M property, a cost segregation study estimates $316K in first-year depreciation (compared to $28K with standard straight-line), potentially saving ~$117K in taxes at a 37% rate.

Cost segregation utilizes the MACRS approach.

Most cost segregation firms will provide a free cost/benefit analysis quote to help you determine if the tax benefits from the study will outweigh the costs.