AndrewI'm not a mortgage broker or lender, so if any professionals in this field find error in my statements above, please set the record straight. 

You'll have to coordinate in advance the exact date that you plan to get them signed and return them promptly, but it is very straight forward and people do it successfully all the time.

However, I can tell you that this would be an owner-occupied loan so you cannot use it on a straight rental investment property.

I also agree with all of @Mitch Messer's points which is why straight calculator reliance or opinions based on it are not going to be accurate. 

If it's a straight buy and hold and you are a first time home buyer, there are low down programs out there that could feasibly work for a buy and hold.

We recently had him on Episode 9 of Straight Up Chicago Investor breaking down each burb.

In NJ, our taxes are all lumped together are and are straight quarterly payments.Also, are you using local lenders? 

As for calculation, it would essentially be straight line so if it is residential you could divide the amount of purchase price attributed to the building by 27.5 (for residential) or 39 (for commercial) and then prorate that for the amount of time during the year you are depreciating it (if only one month then multiply it by .0833 (1 month divided by 12 months).

I like to play everything straight, @Jonathan Craig.

It should be a straight forward rehab.