You can usually do a cash-out refi after 6 months.But, you should know that full, un-tapped amount of the HELOC counts against your debt-to-income ratio. 

I have zero debt and great credit just not alot of reserves.

I have saved up about 40k in cash, have steady income of 70k/year, no debt other than credit cards for monthly expenses, and my credit score is 800 (it was 805 but a lender I no longer work with pulled my credit so it went down to 800).

We spent close to $150K buying and flipping these rentals and I was shocked to see that our taxes INCREASED by several thousands of dollars even though we made such a major investment and took on substantial debt to buy these houses (in the form of a HELOC and an additional mortgage).Is this typical?

In short, your debt on the property has nothing to do with your "capital profit/loss."

If you wanted to know your “return” you could do ROE which in this case is 100% of the value instead of value minus debt. 

@Tim Lee - A few names to lookup:- Peter Fortunato- John Schaub- Gary Johnston- Dyches Boddiford- Bill Tan- Dawn Rickabaugh- Bill Cook- Tracy Z- Jimmy Napier (he passed away, but his book "Invest In Debt" is out there if you search for it)- Mike Cantu- David TilneyMany teaching creative finance today, learned from those listed above, or from someone who learned from those above (and some of the above learned from Jack Miller who you can also lookup). 

You should be able to show equity and debt options to even go under contract.However, if you get something under contract, but don't close, your reputation is tarnished and people will not want to do business with you.I pay wholesalers, they either want 4% or 20% if double close and paid for Phase I, ALTA survey, site plan, zoning analysis, lease abstracts, etc.

your not going to create down payments at 200 a month i can tell you that.. at least in the beginning.those that do this like Steve did  did so with Lazor focus a Dave Ramsey esc. personal debt bible.. etc etc.. 

As I’ve paid off massive debt, I’ve noticed extra money in my bank account that I would like to invest.