You should only have to change when your current software has a flaw or lacking feature that is causing you to spend too much work on a work-around.

Who is monitoring budgets and spend?

Spending on expensive upgrades is not the answer to improve your tenant base in this type of area.Keep the homes habitable, clean, and safe. 

The HELOC would act as en emergency way to tap into their equity if needed - as long as they don't spend it unwisely!

@Luis Cerwin as others have stated, Nov - Jan is the worst time of year to have a vacancy.Majority of tenants live paycheck-to-paycheck, so all their income goes to Holiday spending starting with Halloween, then Thanksgiving, then xmas, then NYE.January is also historically the worst month for rent payments due to Holiday Hangover Spending.

Your strategy takes advantage of your employment cash flow and ability to control discretionary spending.  

You don't have to spend a fortune and buy a house directly on the beach to do well, but your starting price point for a viable option in this market is around $350-$450k for a solid 2-3 bedroom oceanfront condo or around $500k for a 3-4 bedroom house within walking distance of the beach. 

But to me that would be a spending problem, not an income problem. 

@Patrick Braswell Got it. just didn't want you to spend all the time working with your family members if the bank won't approve a HEL.

There are certain things that require experience that DIYers just can't get right or spend way too much time trying to do.