Wave 2 Due on Shelves April-June
Core: Megatron, Starscream
Deluxe: Airazor, Ractonite, Huffer, Arcee (repack)
Voyager: Inferno (G1), Dinobot
Leader: Ultra Magnus
Wave 3 Due on Shelves July-September
Core: Dracodon, Soundwave
Deluxe: Tracks, Wingfinger, Scorponok, Wheeljack (repack)
Voyager: Rhinox
Leader: Galvatron
Wave 4 Due on Shelves October-December
Deluxe: Waspinator, Pipes, Shadow Panther, Slammer
Voyager: Tigatron, Starscream (rapack)
The Commander is said to be Rodimus Prime (voyager sized bot with trailer that turns into weapon platform)
The Titan is the ark, which you can see in the poster below.
Generations Selects: Deep Cover, Transmutate, G2 Ramjet, Artfire, Galvatron in toy colours