If I were younger (I’m pushing 50) and my SO was more on board with the whole real estate investing program I would be moving into a new low down payment property every 14-15 months as soon as I had raised the money for a new down payment.

Is it possible to have a 12 month lease automatically convert to a 30 day lease in the event of a missed rent payment? 

You may want to speak with a real estate attorney as you may be able to deduct the higher than normal water charges from your rent  payments - if you documented everything correctly.

Delayed payments to contractors will only sour the relationship.

I bring up new paradigm here :it's because of too much expansion of money.What I mean by that is because we have lot of money increasing floating around with downpayment as little as 5-20% can already purchase a house with 30 year fixed debt, the number of potential purchasers are increased by a lot, while supply is diminishing, the amount of liquid hard money is increasing, and liquid money is always going to hard asset like residential.if you cut 30 year fixed program and gov no longer print money, the buying power would reduce.

While it's speculative, if you're comfortable with a 35%-40% down payment, refinance and pull most of your equity out if rates come down in the following years—a strategy implemented time and again by experienced investors.

Transitioning from sellr financing to traditional financing on commercial properties, the initial down payment made during the seller financing phase is taken into consideration when calculating the equity you have in the property (make sense?).

My final question is that you said you are turning a profit, but with all cash that is confusing as you have no mortgage payment. 

Since your dad has more capital to invest, you may be able to leverage his funds for down payments or renovation costs while using your real estate license to identify and analyze deals.Market Research: Whether you're investing in California or out-of-state, conduct thorough market research to identify emerging markets, trends, and investment opportunities.

Keep in mind HELOCs are interest only payments, adjustable rates, and will eventually turn into a fully amortized loan (usually after 3-10 years).Cash Out Refinances are great when you need the cash for long term needs or consolidating debt.