I will attempt to answer this even though I'm not the guru on rules.
1)
Quote:Lightsaber Throw 5
Force 5, replaces turn: Choose 1 enemy within line of sight, ignoring cover. Make 2 attacks against the chosen enemy and against each character adjacent to that enemy.
Quote:Cloaked
If this character has cover, it cannot be targeted by nonadjacent enemies.
As you can see from their definitions the LT5 ignores the cover. Since cloaked relies on cover to work they are no longer cloaked. So yes they can be targeted.
2) The cover is ignored for targeting purposes but it still gives the +4 defensive bonus.
3) Most of the powers and skills that say "Sight" still do follow normal targeting rules. It will specifically state on the stat card otherwise, if I'm not mistaken.
Hope that helps and I know eventually one of the gurus will be able to confirm if this is all correct