TL;DR I need a dedicated team, not low-investment part timers
One possible compromise I could imagine is something like three 9 hour days with an hour of emailing/communication/brainstorming the other two days. And maybe once every month or two they come to work an extra half day for an important meeting.
With a 30-50% pay cut, this setup will be positively affecting the burn rate/payroll expenses and it could easily be a better investment than the standard work arrangement. Obviously not every potential team member would be the right fit for this, but I think many would.
This is because those huge projects tend to require a high degree of coordination and planning, and that means the people involved need to be available to the rest of the team. And if they're not available, they aren't involved.