The biggest drawback I am having is calculating cost for repairs & finding a reputable contractor for a fair price - I know nothing about renovations right now.  

Here is a question, would the radio show hosts bet their reputation on someone that was completely out to lunch?

I was wondering if anyone could provide a recommendation for a reputable property management company in Northern NJ that handles small multifamily? 

With that said, not every mortgage broker has an exceptional reputation.

Does anybody have any reputable sources?

That honestly doesn't sound too bad I'm sure maybe if you asked around you can find someone who can do it for slightly cheaper but if they have a good reputation and I would go for someone who would do a better job. 

I don't know the details, but Cross Country is a reputable renovation lender, and has the VA product.

Would anyone know of a good and reputable resource or platform to learn and execute investing / buying  mortgage notes?

For example, I try to rent to families and try for longer durations with renters that will take care of the place and also might put down roots with kids in school etc.Check crime stats, schools, population trends, big job suppliers, colleges, hospitals.

home depot and lowes is a great way to start . amazon is awesome from small to large items and sometimes have sales . some of the contractors you work with will also be able to source materials from their established relationships of suppliers .