I have a question about control & abilities: if you take control of a minion, you can use it's talent; if a card has a 'standard' ability, it happens only once when the minion is played (not when it moves, etc.). Since a minion has to be in play to be controlled, does this mean you cannot use the 'standard' abilities of minions you take control of? Or does taking control of get treated as 'playing' for that first time?
Changing the control of a minion doesn't involve playing it
If you consult the term Control in the rules (below), it says "it is as if you played it" just like all of your other minions, not "you get to play it".
If changing the control of a minion required playing it, you wouldn't be able to play another minion that turn. But I'm sure that's never stopped you.
Control: By default, each card you play is controlled by you. If you gain control of a card, it is as if you had played it: minions add to your power total, abilities on the card apply to you and you can use them, etc. Controlling a minion does not mean you control any actions played on it, but their abilities apply to the minion normally. When the card leaves play, it goes to the hand, deck, or discard pile of its owner.