This looks like a strong deal - what do you estimate will be the ARV?

Then do estimate of the repairs.

You can use the website affordablehousing.com to see the estimated rent for that type of property and location, but it is just a rough estimate. 

Nothing should be an "estimate."

You may need to get a home appraisal, and you'll be responsible for the cost"My question is : Should I have my own appraisal done by a reputable company that would be accepted by banks for appraisal estimates and then request Citizens to do their own appraisal for a request of PMI cancelation.

How much estimating have you done on the costs to furnish it as an STR?

For partial asset disposition (like replacing a roof), estimate the old roof's value using the cost of the new one and write it off so you're not depreciating two roofs.Amending your return might not be worth it for changing the depreciation.

If I use an FHA loan to buy a BRRRR and house hack let’s say I’m starting with $50K cash and I put 3.5% down let’s estimate $12K including closing costs.

We calculated the collateral value of each property, and told him we would be willing to do a release based on (1) a payoff of our estimate of that properties collateral value PLUS (2) a extra fee (profit) to us of $50,000.  

My CoC can only go DOWN since my rehab estimate is pretty solid.