My question is- am I better off continuing to save and buy something bigger/better later down the road OR do I jump into this as a temporary primary residence and future long term rental? 

This is the one aspect of investing that as opened so many doors for me and continues to do so.

I am deliberating two possible scenarios for myself in the future to continue down the path of working for my self and family as well as investing.Scenario:80k-100k cash on hand not in a rushOption 1 potentially:Find a older duplex 30-40k for cash with a higher estimated arv than the projected rehab, rehab property, rent, refinance.

Some of that should take shape on its own as it will continue to be much easier to finance owner occupied units in the building rather than investment. 

We continually push rents higher and higher.

Three possibilities when you get a mortgage in a rising rate environment, assuming 30YF financing:- Rates continue to go up, you're glad you got what you could when you could.- Rates stay the same, it's a wash. - Rates go down, you refinance and harvest the cashflow improvement.

I had no idea about the obstacles that needed to be overcome in getting financing, finding deals, etc, but I kept learning and reading and at the same time finding a job where I could have steady income while I continued to learn.

That puts them in a tough position because they often don't have the resources to continue on their own. 

There is a married couple, with 2 kids that claim they have (570 credit score), that their credit issues are over 5 years old, both are holding jobs for over 3 years, with enough income to cover rent, and they are willing to provide a co-signer.Should I just continue to wait for the application that qualifies completely or should I look into this one more? 

Doing that and continuing to pay down the loan should allow you to reset the equity at some point through refi or heloc and roll that into a new property.