I bought a property last year that I give credit to PR for helping me get and we will make about 300k on it.

MichaelJust for full clarity, for 195 to apply to your expenses they would need to be otherwise deductible in the year paid (but for the fact that your business has not yet begun).

Should one or both parties apply for mortgages together?

Ideally I'd like to find a LINE of credit of some sort.

I prefer local credit unions & State banks.  

Your credit has to be above 580 for 3.5%.I would be careful when tapping into your current property's equity.

Then in six months I apply for a cash out refi. 

You'll learn a lot and be able to apply it to future structures.

If you "jack" the rent up (even if you find a tenant willing to pay it), typically the appraiser will not give credit for additional value above and beyond what market rents would determine.

Since you allow people people without the credit or means to buy.