So my question is what are the pros/cons of both methods?

I am intrigued to see if this method has been done.  

I actually just read an article to inform myself and it seems that banks use more than 1 method to determine the value of a property such as this one.1) They compare to other similar buildings2) They calculate how much it would cost to build an identical building3) They use the revenus and expenses (this method gives the lowest result)Perhaps my real estate agent was considering some of the other methods and took into account it's amazing location and the actual municipal valuation.

The easiest method is to have all tenants on a automatic renewing M2M.

Using the 4 square method and every time I do a calculation my ROI is never above 6%.  

Im a general contractor from NY looking to get into my first flip as well and I've never heard of that method before.

If I have to go with the 27.5 year depreciation can I use the double declining method?

I did however, just by 2 touchless (no spinning brushes) automatic (no people) car washes myself about 6 months ago, and can to some degree speak to the work and one method of purchasing that business. 

I've been reading about the brrrr method and it really interests me and would give me the opportunity to buy multiple houses (one at a time of course) and be able to cash out and use the same money to buy the next property. 

I agree with you Steve Vaughan, and also Jay Hinrichs, that is a very good method to move forward in one of these situations, leniency is key, in this business, but there is a live between that and being taken advantage of. give them a time frame to get caught up and give them some social services resources to help the situation, I'm sure you will be glad you did.