On the other hand, if it's totally within my rights to keep the whole deposit, given they are breaking a 12-month lease after 1 month and that I've done everything in my power to address their issues in a timely manner, that would be preferable.

This equates to $700,000 in spending power at 20% down.

Do you have the downpayment or collateral power to keep scaling4.  

Can I expense materials the same year as I was doing all the work myself and the majority of work was mostly fixing non-working, absent, hazardous or leaking things (stairs, faucets, some plumbing/pipes, electrical, non functional door handles, some trim fixing/replacement, painting, blinds) in order to bring the place to rentable condition?

We currently pay water, and the residents pay electricity.

When you are starting out debt can be used as a powerful tool.

The biggest thing is to find a trustworthy Pluming/HVAC/Electrical tradesperson/company.

Outdoor complete kitchen with water, electrical and drainage 5. 

If anyone needs any basic advice on electrical, tiling, drywall, moulding and work of that nature I would be happy to help as my abilities allow. 

I have one who started as a cleaner but is capable of cleaning, painting, caulking, tiling, light electrical and plumbing.