It’s not that complicated. There is no buyer EV tax credit on a leased vehicle. It’s just coincidence that the rebate stack may add up to $7500. There is a buyer EV tax credit on a purchased/financed vehicle. Often Ford dealers will reflect this purchase rebate in advertised pricing, but it can’t be used with a lease.
The main problem is that you don’t qualify for enough of the conditional rebates to reach the best possible lease price. On a Flash, this should be a sub $500/mo payment. (if this is actually an XLT is terrible).
See this offer from @LightningAuto