Quickie: when I 'gain' movement points by an effect, does this mean I can use them immediately or only when I activate? Thanks

If the movement points are gained outside your activation they must be spent immediately or lost. If they're gained during your activation, they are added to your movement point pool. (Unless it's a special action, this need to be spent during the special action)

If the ability is applied during your activation (including at the start of your activation), then the movement points get added to your MP pool which can be spent normally as if they were gained from a move action. This includes stuff like Beast tamer or Dewbacks abilities.

If the ability is applied outside of that figures activation, then that figure can interrupt to spend them immediately - and any he does not spend immediately at that point are gone (they do not carry over). This includes stuff like gideon's command or an officers orders.

There is a 3rd possibility - if the ability that gives you movement points is part of a special action (one of those actions with the little bent arrow thing indicating you have to spend an action to do it - like the command card Urgency), then those points have to be spent solely in the execution of that special action. Even if you performed this action during your activation those movement points do not go into your MP pool, but rather have to be spent before you can take any other action, and once you do take another action any leftover points from that special action are lost. For example - if you play urgency you cannot move with half the points then attack then move with the rest (whereas you could if they were normal movement points in the MP pool).