Item #1 of course goes nowhere near following I-4 toward Daytona; it might most likely involve upgrading the route from Jacksonville to a prospective terminal location for the Auto-Train and thence to Orlando.
Any service to Miami not provided by idiots would then follow Brightline across to Cocoa and then south to Miami on high-speed track already built and paid for.
Alternative #2 is obviously for the Brightline extension already in the works for Tampa. Why turn down OPM to get the result they’d be willing to self-finance? The only alternative view would be to make improvements to the existing somewhat-rickety route from Orlando down to Tampa/St. Pete… while Brightline arranges for a higher-speed version to follow when the real-estate development justifies it more completely.
Since the grant amounts are consultant chicken feed, you should identify who the ‘corridor sponsors’ are, and what their priorities might be.
Brightline has passenger franchise/rights on FEC from Cocoa to Jax, so… That $0.5M is probably to “study” the route. There are really two alternatives for Jax to Orlando. The CSX line and FEC. The FEC route gets you St. A, Palm Coast, Flagler Beach and Daytona. The CSX route gets you Green Cove (Jax suburb), Palatka and the northern Orlando suburbs (Sunrail territory) The FEC route is almost dead straight and level. The CSX route is a bit more wiggly. The CSX route has almost no freight traffic. The FEC route has a half dozen or less freight each way.
Going Orlando to Daytona is important IMO. Unfortunately Sun Rail is going on the cheap to Deland ( county seat ) instead of new expensive ROW to Daytona. Brightline will only connect a very small potential passenger demand that Sun Rail could have done. Sun Rail taking all the potential traffic off I-4 Daytona to Poincianna maybe sometime in the future might happen but not now.