Barret had fallen from Sector 5, instead of Cloud? Would things have gone the same way at all?

(The stage awaits you, Sephex.)

Side note: did we ever find out how President Shinra knew to be there, outside of the security scan gone wrong? Seems awfully convenient that there was a whole goddamn squad there, but then Biggs, Wedge, and Jessie all die fighting against Shinra so they're unlikely to be spilling the beans. (UNLESS...!)