Since seeing this post, I have been pouring over the rules to see if I can gleen anything from them. Nothing definitive. So... based on this, I would rule the following:
[*]The Seekers will first continue to move toward the "last known" location of the cloaked ship.
[*]Once the seekers reach the "last known" location, they will continue to move in a straight line until they either {a} leave the map, {b} enter a hex containing other enemy targets, or {c} the cloaked ship uncloaks.
[*]If the cloaked ship uncloaks (either before or after the seekers reach the "last known" location), the seekers will automatically regain their lock on the cloaked ship and will continue in their mission to attack that target.
[*]If a seeker, having lost its target because it cloaked, finds itself having moved a fixed number of hexes from the "last known" location without having found an enemy to attack (ie: 15 hexes or the board-edge would be conservative; 30 hexes would be liberal; 45 or more hexes would be downright generous), then the seeker self-destructs or otherwise becomes inert.
[*]I would apply the same rules as above to seekers that lost their target because the target was destroyed before they could reach it.
Those are my thoughts. Anyone else want to weigh in?
As far as using Seekers to attack Fighters/Strikers -- sure. You could even, if you wanted, use Seekers to attack other Seekers. That would, actually, be kinda cool...