We have about 100K in equity and have some cash on hand but not enough to cover a 20% down payment, loan costs, and rehab costs so the HELOC or second loan seems to be needed for our first deal.

And if you did are there banks that would give the loan without a down payment to start the plansorry for the late response. 

You'd probably have to figure out how much of a down payment you'd like to receive upfront, how many years you'd like to spread out the loan, interest rate and payment amount. 

New Bank Loan Traditional Subject To Take Over Existing Loan - has already been paid down some Purchase Price $400,000 $332,196 (Take over existing loan) Down 20% $80,000 $10,000 To Seller Loan Amt $320,000 $332,196 (Take over loan) New Loan Payment Rate 7.75% $2,293 $1,465 Take Over Payment Rate 3% Difference $828 Your Savings per month Other $0 $0 other Loan Origination Fees 2% $6,400 $6,400 Your Savings On Loan Fees Closing Costs $3,500 $3,500 Closing Costs Cost for length of Loan $825,307 $490,512 Your Cost for length of Loan $334,795 Your Savings over Life of the Loan Using Bank Cost to acquire $89,900 $13,500 Using Us Cost to acquire $76,400 Your Savings Just By Buying Using Subject To Total Savings $411,195 Your Savings Total w/Subject To

Even if interest rates become outlandish, if the buyer uses lending to buy, he has a much higher payment, which he may not even be able to afford.

Can you afford the payment?

setting this as a goal will give you lots of specific action items to do:-save up for down payment, closing costs, and reserves-talk to agents-talk to lenders-look at propertieshttps://www.biggerpockets.com/real-estate-investing/house-ha...

There is an acceleration clause is most deed of trusts, that is, his mortgage document that calls for a full payment of a mortgage if the title is transferred in this manner, but people do it all the time and accept that is the mortgagee/lender ever exercises this clause then you'll just have to refinance the property and since you were paying the mortgage and have proof, you should have no difficulty in refinancing the property. 

We have enough to cover the down payment and closing costs, but not reserves. 

If you strategy is to build a rental portfolio as fast as you can then, you want to refinance at the highest available leverage. (75%) That allows you to preserve your capital so you have down payment money for your next deal.