The FARs ( Federal Acquisition Regulations) do not allow a company who does a preliminary evaluations to than design or bid the construction. This is not true of MA, The present Pool company will get the design contract. They are by definition predigest.
I believe that the pool can be refurbished for a lot less money, somewhere in the 600K range. Fix the present structure, new filter system, new puerperal pad, expand and refurbish bath house. Do nothing to the septic system (It works fine for the present capacity)
We should do our due diligence and get independent Eng evaluation, especially for a simple refurbishment. Once again, gee, we have a flat tire, lets buy a new bigger and more expensive car. How not to spend Tax Payers money!