My business will pay about 2500-3000 for that portion.

If I were you I would do further research with environment organizations that could give you more information on how to test for it, how to remediate it and how to make that decision.I will say that if you are planing on adding/upgrading the Air Condition I would suggest you work with an asbestos abatement company to do the work for that portion of the house.

A portion of the property is short-term rental, so we have to trickle in repairs over time or during winter.  

.- Rehab money to fund the first milestone if the rehab portion is paid in draws in arrears. - The purchase deposit - anything not covered by the loan.

The top portion of the first paragraph of the contract should say “and/or assigns” in it for sure.

I think I know where I was making a mistake in the refinance portion

You will only be able to allocate the 1031 proceeds into the investment portion. 

I would contribute all or a portion of the down-payment and my name would be on the deed.

Hello All, I'm ready to BRRRR my first property and after reading the BRRRR book I want to ensure I have the refinancing portion sorted before purchasing. 

If you rent a car, you can deduct only the business-use portion for the expenses.Meals and lodging.https://www.irs.gov/taxtopics/tc511