Student loans are usually one of the cheaper sources of money, so paying it off is effectively only investing at the low rate of return.

However, if I open one in Florida, I can be my own registered agent, but I'm wondering if there are any drawbacks to being a "foreign LLC," when my rental is in another state.

Oh I see foreign national.   

You are sourcing a property out of state, haven't seen the property, don't know any investors or providers in the area, don't have an attorney or your own title company - how do you think this is a valid business plan?

I am a wholesaler and have learned a great deal from my local REI group, here on Bigger Pockets, and from other sources.

Additionally, does anyone recommend how to find this info. for DMM and Cold Calling (List source, CoStar, Reonomy).

All of our pre-licensing education, testing, and continuing education, assumes that the only place you get a mortgage is by calling one of us (biased source, much?)

That being said, there are not institutional lenders going to 90% 2nds on investment properties but you can then shop private lending sources or secure seller financing.

My llc is in florida and i have property in nc , i must to register as foreign? 

If you can obtain a job and your employer can vouch for you that it is indeed a reliable source of income for you, they will likely be accept that!