I'd suggest making sure to get a good GC/construction company for repairs.

I would suggest that once you are done reading that book - give it about a week and read it again. 

I am open to suggestions.

I don't use Stessa and never have so I don't know what's going on, but I suggested they take a look at Baselane, which is what I use.

What or who do you suggest I speak to or learn from to better understand my options for mortgages?

Quote from @John Reagan Johnson: I am new to the real estate industry and am looking to connect and exchange businessIf you are new I would suggest something totally different. 

I am looking to buy a multifamily in Jersey City for STR, any suggestions, what area will be good for STR and weather number make sense at this time.

Any suggestions I appreciate in advance.Worst case, I'll just create something for him and walk him through things as he goes, but I'm thinking, why not document it for us both (no plans to publish or anything though)!

Anyone have any suggestions?

You can read a book and multiple books, but unless you are out there doing it (I.e. getting bids and getting contractors to truly get you an exact estimate) you will be far off from the numbers you want and may even lose money on the flip/rehab.The best advice I would suggest in my experience is that you should get into the line of work by either partnering with someone or working with someone on some projects prior to going into a flip on your own.