Some of the credit cards they get you do not report on your credit profile unless you don’t, But you would be the personal guarantor  and they would look at your personal credit As a determining factor. 

Those factors can jack up that $80k revenue real quick

Yes, you pay interest whether it's in use or not, but the downsides of a HELOC outweigh that factor, in my opinion.

Building one will cost you about $200-$300 a sq/ft so be sure to factor in those costs as well.Renting by the room will probably bring the most cash flow, but one has to be alright with sharing a space with multiple people in exchange for more money.Good luck getting started!

You can deduct the cost of labor and parts to maintain or repair your business assets, as long as the expense doesn’t prolong the useful life of the asset or increase the value of the asset.Tangible Property Repair Expenses That Are Deductible:Replacement of LightingRoof repairsResurfaced external or interior floorsResurfaced parking lotsInterior or exterior paintingReplacement of doors and windowsRekey locks

So multiple factors.

Factors that may help - sold off market, showing rental history of the purchase before and after, if you have a history of buying long term rentals.

It depends on so many factors.

But the numbers vary lender to lender and some will make allow for other compensating factors to offset low population / rural numbers.

Having multiple deals going on shouldn't be an issue for most lenders as long as your DTI and other qualifying factors allow for it.