If not, you need to speak to the police.

Normal roof job is the shingles and any decking that is beyond saving and generally speaking most decking stays.  

You are speaking of broad categories, when the fact is that individual deals are what matters, not categories of investment.

Selling a 4 Family in Athol, and have an offer on a 3 family in Athol as we speak. 

This type of a question is so specific to you I would encourage you to speak with a local lender to get the answer 100% correct. 

@Jack B Slack I would encourage you to speak with a local lender and discuss this.

@Stacey Carroll I'd speak with an attorney about option #2, that sounds interesting, but I'm not sure.

You can go to your local home depot and speak to them about your ideas on renovating/retrofitting your space, register as a contractor, it would save you a ton of money if you are buying yourself,  I am sure you can get someone competent and affordable to assist with your schematics, designs and cost.

I would speak with a commercial broker and see what commercial banker they would recommend for this type of deal.

@Andrew Fisher, if you don't have a specific deal on the table, lenders like to see that you've had experience and have a goal in mind generally speaking.