Technically if they called the note, would I be able to get a better rate on the next loan?

I recently shifted my career to focus mainly on real estate investing, so I'll need some help with creative financing as I don't have a standard 9-5 like many others.

In this particular case, I have a property I'd like to get a HELOC on to then buy another property.

Considering a duplex as a primary and rent out other unit. How do interest rates play in this scenario? It would be a primary home but will I have to pay higher rates because it’s a duplex?

The one item I am not clear on is the 50% contingency on top of the contractor bids.

Im a college student currently working on my capstone project where Im aiming to build a property management software.

I’ve had it on my radar for a few years and cost vs revenue doesn’t line up.

My water usage bill is the same,  general lability coverage is the same, if and when I have to replace my water service line it will cost the same, the cost for my lawncare and snow removal costs the same, exterminating services cost the same and the list goes on.   

Curious on your thoughts.

Lets say I close on a house in April 30 and am charged the local taxes on the closing statement from Jan to April.