I'm currently fixing and flipping a house in Hackettstown, and would like to receive some recommendations.

Don't wait too long because rates are going up, but fix your credit and buy a multi family property. 

What is the issue and how can in fix that?

It is a Fannie Mae ARM with the first year being X and the remaining term of the loan increasing and becoming fixed by 1% the following year for the remainder of the 30 year loan.

Applying for a conventional loan and lender is telling me that it will be 25% down, fixed rate, and 30 year. 

I did not use a property manager but I used a trusted friend to be in charge of the properties; he was able to move into the houses once they closed, take care of the little issues that needed to be fixed up and interview renters (we used Smart Move).

Also remember that your mortgages will stay the same (if you do 30 year fixed) but the rent will increase every year.

We are working thru the abandoned title process, but have interested parties wanting to rent the homes and fix them up.

As we are fixing up the parks and selling manufactured homes in spaces, we have been using seller financing since traditional financing is very difficult and expensive for the buyers.

I don't wholesale, but I buy dilapidated properties and fix them up and rent them.