Seems like vader and luke can attack 2x with their special abilities?

Depends, ffg usually limits actions to once per activation (free or otherwise) and the preview on both cards abilities states "an attack action"

My bigger question is does force saber throw count as a "force power" or and "attack action" per the text at the end of the card for the purposes of the action.

being able to aim->move->saber throw 3 red with reroll and pierce/impact 3 will be fairly big, especially if he uses that command that gives him 2 activation's to follow up with a second (random) activation to try for cc

it has an arrow which i think means action the double arrows like on choke are free

yes. but on the end of the saber throw card it says "this is treated as an attack action"

I *think* that means it can be combined with vaders relentless to allow the activation listed above. (which differentiates him from luke in that he is restricted to free melee attacks)

if you had both choke and saber there is the possibility to follow up either before the move or after that sequence (you'd have to attack immediately after the move or you've lost window of opportunity) with a choke on the remaining unit if you started/got into range 1. That card doesn't list itself as an attack action.

At the demo, they said figures were limited to one attack action per activation.

That's the same as Imperial Assault, and I'd expect abilities here to be similar. There will besome abilities (like Force Choke) that are attack-like but are not attacks and so can be used with an attack; others will explicitly be attack actions and can't.

Makes me wish FFG would use some of the language from other games and preface an ability with " Attack: " or " Move: " or whatever so it's clear.

The only action that can be used more than once per turn is the move action as stated in the TC video IIRC; all other actions can only occur once.