The down fall is a Heloc can "Never" be used as an asset or for PITI reserves required when buying a new Primary or investment property.A heloc can also cause major issues with credit and one slight hiccup or missed payment the bank or lender who is holding the Heloc can close or reduce your line of credit.

After selling one and using a 1031 exchange to buy a fourplex in Chicago, he reduced his interest burden by 20% while boosting his net incomes by $1,500 per month.

You never skip interest, you just reduce principal by $600 so you pay less interest.

If we do cost segregation how much would we reduce our taxes by?

The problem is, that's not proper accounting because a credit card is a liability, and doing this workaround will reduce your assets rather than increase your liabilities, which totally messes up your balance sheet and debt-to-income ratios.  

Many local businesses that operate in the downtown area by the state park (including some famous attractions) close for the winter or reduce hours.

This reduces exit options and affects the value. 10) Small number of small units is the most expensive residential development there is.

So if the deal goes right, I get a return in the form of equity on the house, and my rent is also reduced since let's say, as part owner, I would be receiving a portion of the rent (which I would be paying...).

I have great tenants but my property taxes have increased significantly so my net cash flow each month is reduced.

This would help reduce the amount needed for a bridge loan to fund the acquisition and renovate the four vacant units.