My question is is there a difference on whether the seller financed note is secured or unsecured with regards to a possible refinance?

you can borrow with unsecured promissory note.. this is quite common..

Nearly all unsecured LOC's are extended to those with significantly more liquid assets than the principal. 

@Todd Krzeminski I was more worried about the company solvency over the economic downturn but agree another huge hit like 2008 and the first to go are unsecured loans.

I'm not going to even bother looking at their site.....you don't get an unsecured cash line of credit for $60k without some substantial/decent financials, and a business history.....period.

It will be an unsecured loan otherwise and cost you dearly.Jim.

Does an LLC require that the loan be secured with a 2nd on the new property or can an LLC make a unsecured loan to a member?

They are middle men that help you secure multiple lines of unsecured credit with low to zero intro rates.

@Miles Stanley I used an unsecured bank loan to finance the rehab portion of a BRRRR on my last deal.  

g=7wFf )Keep in mind, using the 1% rule of thumb (monthly rents ~= 1% of basis) and 50% expense rule of thumb (operating expense and vacancy ~= 50% of gross rents), unleveraged, results in 6%.