And it will probably be through the Excess (Surplus) Lines. 

We don't want to do a cash out refi and lose that interest rate, so we are thinking of a HELOC.Here are some questions/situational facts:Do most banks generally let you do a HELOC for investment purposes, or would we have to go with an investor-specific lender?  

I will be losing roughly $300/month in cash flow doing this.

I'd lose out on all that appreciation and in exchange I up my cash flow from $1K/month to $5K/month..

**except you could lose all your money

@Nisarg GandhiUnfortunately, you may lose out on the partial exclusion if you rented the house prior to sale.The exclusion is dependent on sale as a result of the move.

Do your best to be professional and assure them there is no way they can lose money.

If you're on the inside, you stand to gain, and if you're on the outside, you stand to lose.

Pulling cash from your personal residence is certainly an option, but you must be careful - if your investment goes bad and you lose money, you will be stuck with that extra payment.

Instead, you could lose money.