Is it information or strategies related to different property types or how to use debt or seller financing for property purchases? 

The key is how the deal was structured legally.. debt or equity.

Does your end point include paying off your debt or do you plan to let the mortgage payments pay off your properties naturally over time?

For example, I am a little concerned about some aspects of the business cycle recovery and a potential for a double-dip so I lean toward the safest part of capital stack which is debt (or low-debt equity).

Yet another important question would be Is this for long term debt, or are you acquiring a distressed asset that requires short term debt (typically what's known as a hard money loan) for a year or two while you acquire and stabilize the property, before transitioning into one of the long-term debt options above?

Any reduction in debt or cash received may be treated as a taxable boot, resulting in potential tax liabilities.

My experience over 48 years investing in real estate 20% of foreclosures result of circumstances beyond debtors control80% of foreclosures result of poor decision making, inability to manage life/money, etc (self inflicted).It can be argued that our education system shares responsibility for the latter.

Don't ignore them, call and see how they can help, some will let you defer a payment to give you some breathing room.Be honest with yourself and your debtors - build a bullet proof plan of success forward and don't beat yourself up.

Most of the HELOCs I have done were to pay off higher-interest debt or to use toward a home renovation to increase property value. 

Only folks that I saw make it through the melt down were very well position investors ( many of mine have or had zero debt) or massive equity and RESERVES.. this does not describe the average SFR investor especially those starting out.. those starting out with maybe 50k down and 50 in reserves can and do get wiped out quite frequently.Id imagine in many of those situations as opposed to walking away from their properties, many of those folks could have simply sold them.