Ana,Based on experience and this market me personally I would avoid a HELOC for a few reasons.

My question is, it recommends that tenants maintain certain area on the property there responsibility to keep clean is so any recommendations?

I am in process of subdividing the lot currently to build a new SFH for myself and keep the existing home as a rental.

The location and high rent demands keep investor buyers interested in the market. 

My PM used to have a person who did the payments and every year around Feb, she'd send out an annual statement for your taxes showing how much you got in rent, spent in repairs and management fees. 

Based on what you wrote, this has nothing to do with the tenant and them not being home is not a reason to keep their deposit. 

Fingers crossed in 7 years I have not had to test my coverage, but in the area of my rentals a golf cart is expected with the rental.When they crash into someone else, did that person sign the waiver too ?

Lastly, our DTI is maxed out per every lender we've spoken to recently as all the properties are mortgaged in our personal name.

It's not 100% accurate because one person might have a smartphone and one or two tablets, but it's one more data point that helps me keep tabs on my owners' properties.Hope that helps!

Note ADU addition in a MF zoned area may be comped with a duplex but I personally think this is wrong as a SFH with ADU is not a duplex.- it is cheaper to buy a property with an existing ADU than adding one   In addition you would receive RE purchase financing.