I have signed many times as a co-guarantor (the words "jointly & severally" still make me sweat) on a multi-million dollar commercial or construction loan, where I only had fraction of the ownership interest.

I would do this if you can’t get a co-signor.

You can try to find a co-signed that is willing to sign with FHA but that’s a big ask for someone to do.

So he was required to get a co-signer but then this person wasn't able to get a co-signer.

Just something to consider if your long term strategy is to sublet a co-op apt.As for NJ, I'm guessing you'll be priced out of downtown JC and Hoboken.

I do not want to do a co-op.

As a beginner, you can learn a lot from your uncle with a few rentals in another state or a co-worker that's on their second house hack.

My name is on the deed for my primary house with my uncle as a co-signer (his name on deed as well).

You'd need to tell them in advance that you have your own agent, and ask them if there is a co-broker commission being offered. 

The other being to bring in a co-borrower or cosigner.