@Levi Ramirez It's great to see that you are thinking about the impact of your building on both the environment as well as the tenants. A couple things to keep in mind to make the project a little more feasible.
Do construction companies in the area have experience with ICF construction, It seems pretty popular in the south and SW but if its new to the builder you will pay a premium. Have you considered other similarly efficient methods of construction such as double stud, exterior insulation, larsen truss walls? Concrete has a pretty big environmental footprint so reducing it to uses that only it can accomplish is something to keep in mind.
Do you need to hit net zero for the project to be successful? The ability to get the amount of power out of solar arrays for complete energy independence is far more attainable than it was even 5 years ago but it can still be a challenge based on building orientation and the size of the array you can fit on the roof. Getting close to zero is a huge step in the right direction and may be more economically feasible.
Personally I'd just submeter the building and avoid the headache of managing and trying to justify energy costs to tenants, that said some way of quantifying their savings and reaping the benefits does make sense. Maybe you provide them with an opportunity to receive credits from energy savings and find a way to translate that into increased rents?
As far as the reuse of plans, it works differently for all architects but just be upfront about your intent and they can work with you to develop some sort of licensing agreement. In theory, you will need to site the future buildings as well and go through the permit process so maybe they handle that part on the future buildings and only charge a small fee for the design license making the following projects more affordable. Big picture, the architect fees are not the expensive part of the building process but I get that every bit counts when trying to make things work.
Shoot me a DM if you want to get in the weeds on any of this.