Im looking into a few different Areas and looking to really narrow down my search area

Go to Amazon and shop reviews or narrow your question?

I believe finding the right team is the first step and will help narrow this down quite a bit.I'm primarily interested in 3/2 SFRs in B/B+ neighborhoods and value a low-risk tenant base and good neighborhoods over super high cash-on-cash returns.

You can get a map of them online and then overlay the states/cities where you are comfortable and it might help narrow the focus.

It sounds like this is something you could handle just fine considering you and your wife's experiences.2) Speak to a realtor experienced working with investors to help narrow your focus, pre-qualify you, etc.3) Off the top of my head a multi-family purchased for around 1.2M with 35% down would cost you around 4K per month for mortgage, taxes, and insurance, and that wouldn’t take into account any rental income, and it would also leave you a good amount of cash post close.

I had gotten some initial quotes in the beginning from Mortgage Broker B and he said he would send a loan estimate -  which i never saw - I discovered it today and his rate is ½ point lower and closing fees are about $3,000 less - what is the protocol to having Broker A meet new rate provided by Broker B?

Of course, you don't need to be a Realtor to make these connections but it certainly helps.I began investing 6 years before getting my license but working in the field full-time has certainly helped me narrow my focus and monetize some of my relationships. 

Is there another way I can narrow down my search to which neighborhoods would be the best to invest in.

Class b and C only. 

I can do a search on sold homes and I can narrow it down month by month and see how many more houses sold, but its tedious.https://www.zillow.com/research/data/