Who is the licensing board for septics in your area? State, county or town? Whoever it is, get the book, take the test and become a licensed installer yourself. You probably have access to all the equipment you will need for install, and they are dead simple to build. I put in half a dozen out west on the spec homes I built. All you need is an engineer who doesn't want an arm and a leg, and they are pretty easy to come by. Actual build time, including inspections, can be squeezed into two weeks.
If you are planning on city water, it only gets easier, as you don't have set backs from wells to consider.
I would recommend tile and stone over any kind of infiltrator system. Easier, cheaper and less prone to problems. Might be a bit more labor, but cheaper labor.

__________________
On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

https://media.giphy.com/media/X3nnss8PAj5aU/giphy.gif