I'm starting to research guidelines on using HELOC money as a downpayment - i'm seeing mixed things on-line.

I'm 27 years old and currently completing an Environmental Tech diploma and am extremely broke (student budget).

Worth it to be in the mix and to have your pulse on whats going on in the community...

I did it with a new truck when I started by the book (with a calendar) until it was fully depreciated, but today  for me on just a few rentals, the recording keeping costs would outweigh the deduction and inconvenience (so I have left off vehicle expense and no vehicle depreciation last few years) but sounds like you may be using your car more and could be worth the time to be bullet proof....There is a potential gap in the reality and rules for me (see my mixed use life below), but if you have an inclination to track miles and purposes and facts closely, it is a nice potential deduction (and what your vehicle has on the dash board is not enough, but some of the apps, like a mileage IQ, could have potential but even those may not be adequate until full tested/vetted in my view, but tech is promising and they make some strong claim...).

Anyway, to answer you question - a number of the engineers you'd engage with the build of your complex will help you find your soils/geo-tech guy.  

Broad based strong economyWorld class education and healthcareManufacturing, high tech, you name it, the biggest names are hereAmusements, professional sports, recreation and cultural venuesThe beachPerfect year round weatherTourists and business people visit from around the worldEvery mid to major airline flies in to both Orange County and LAXBEST OF ALL - Qualified tenants and buyers. 

I agree with @Donovan Castaneda, you need to take out a percentage for vacancy (I do 10%), and depending on the condition of the property, a percentage for maintenance (I like to start at 10%, but love to be able to build in more, as I sometimes mix maintenance and cap ex).

Check it out https://www.biggerpockets.com/forums/223/topics/243750-my-first-mixed-use-muli-unit-brrr-recap

Personally, I think a good mix is the right idea.

He definitely has a tech savvy, modern approach to marketing.I would also echo the suggestion of the BP podcast.