That first map has nothing to do with this project. That map was related to government-run high-speed rail line. Then Governor Rick Scott killed that project way back in 2011. The Brightline/Virgin proposal will definitely not go to the Orange County Convention Center. Additionally, I don't believe there will be any stops between Orlando and Tampa (if that gets built).
As for the second map, the east/west part of the green line will never happen because it would require purchasing the right-of-way through what I assume is privately owned land. It would also likely require zoning changes.
The blue line runs along Osceola Parkway. While it's possible to run a train line along the road, Brightline/Virgin would need to get approval. According to Wikipedia, Osceola County maintains that road.
The red line is the Central Florida Greeneway (State Road 417). That road is owned by the Central Florida Expressway Authority (CFX). Sticking to one route controlled by one entity makes things much easier for Brightline/Virgin. According to press reports, they've already started negotiations with CFX.
Based on that fact as well as the permitting issues that Mr. Drauer noted in earlier posts, I think the red line route is the only logical choice. As much as some of us would love a train station at an existing site at Disney World, I think that's just a pipe dream.