We plan to install a couple systems for ourselves and clients this week.

As a manager, I would recommend that you hire someone locally to do the design & furnish & install. 

Anything you install will be less robust than a utility provided meter which I believe have a list of legal protections regarding tampering.

Install a privacy screen between the pool and the camera's sight line.

Once the new pit is installed we’d install aproper vent to restrict the sewer gases from getting intothe home.

My worry is that it is almost end of the month and he still didnt do anything at all on the project.What are my options if he comes on May 1st and tells that he has no money or that he will pay in installments?

I've begun volunteering with Habitat for Humanity to gain more confidence in DIY improvements. 

What I'm really doing is creating a "workshop" space that's part of the house that can be used towards a business write off, but can also be easily converted to living space with plumbing/wiring already installed in walls/floors.

Also, I would be very concerned with thinking you can DIY your first renovation.

I would make sure if it was installed in or above a finished space that it had a pan underneath it in case of a failure to eliminate/reduce possible damage.