Most lenders require proof of someone else paying the note for around 9-12 months so that the debt isn't counted in their DTI calculation.

So for example I'm very conservative and don't want any debt on them because I feel this hardens them in case of a severe recession.

We buy at a discount and pledge our legal right to collect the debt (a collateral assignment agreement) as the collateral for the private capital loan we take out, which is backed by the value of the real estate securing the 1st loan.  

Unsecured personal debt is often from institutional sources, but at rates of 9-20%, fully amortized over 3, 5, or 7 year terms (not interest only).

Any existing debt?

When your LLC takes a loan, expect as members to personally guarantee the debt.

This eliminates the problem of increasing your debt and damaging your credit score.

If you are open to non-traditional methods of financing, you could use a debt service loan to bypass that requirement.

You can claim to be the best guy in the world at finding and analyzing deals, but when the market turns against you, and you just went all-in, even on the best relative opportunities that market had available at the time, there is nothing you can do to prevent losses, especially if your debt has a maturity date that will force your hand.Timing the market is an interesting concept. 

You have used home equity lines of credit to purchase investment rentals and want to know the best way to pay down the HELOCs.Between the two properties you bought, after expenses, you have $250 a month positive cashflow to use.What I like to do is pay down some principal every month with my positive cashflow.I use my extra active income from real estate commissions helping other investors to pay down the principal even more which just frees up that credit for me to use again.I know I can refinance the HELOC debt before it changes to principal and interest as it is just interest only payments as yours are.One difference is the cashflow, I have greater positive cashflow and could make the principal and interest payment in the future with the extra cashflow I already enjoy.I always get HELOCs on my income properties as well after purchasing them to pull out as much of my downpayment as possible.