Just to check, but can you buy the costumes you unlock through character stories day one or do you have to wait for the store in March?
This article doesn't mention a single thing about 1P vs CPU other than a Challenge Tower like CPU fight with unique bosses.
http://www.eventhubs.com/news/2016/feb/12/street-fighter-5s-lobbies-will-support-two-players-initially-eight-players-march-spectator-mode-will-be-added-then-info-other-game-modes/
Good news CPU mode added in March too (for those that care)
This article doesn't mention a single thing about 1P vs CPU other than a Challenge Tower like CPU fight with unique bosses.