A good analysis, bringing up a few points I hadn't explicitly considered. (Which is, after all, why I started this thread, even though I expected a karma hit for it.) I had been thinking of the AI's focus on the one particular ship to be primarily based on limited interplanetary bandwidth, but I'll probably end up adopting your 2, 3, or 4.
As a relatively minor aside; at this point in the plot, Our Heroes don't really have any idea who the AI's creators actually are. Even limiting the candidates to those with means, motive, and opportunity still leaves a fairly lengthy list - and as Our Heroes' home base is an asteroid colony with a population of a mere few thousand, it would be rather impractical to simply go after every group on that list all at once... which, at least, leaves room for the next subplot to be written.
One plot-thread in my pet SF setting, 'New Attica', has ended up with Our Heroes in possession of the data, software, and suchlike which comprise a non-sapient, but conversation-capable, AI. There are bunches of those floating around the solar system, programmed for various tasks; what makes this one special is that it's evil with a capital ugh - it's captured people inside VR, put them through violent and degrading scenarios to get them to despair, and tried keeping them in there, for extended periods, until they died of exhaustion.
Through a few clever strategies, Our Heroes recognized they weren't in reality, engineered their escape, and shut down the AI, with no permanent physical harm done to them (though the same can't be said for the late crew of the previous ship it was on). And now they get to debate amongst themselves - what should they do with the thing? What use or purpose could they put such a thing to, that would provide a greater benefit than the risk of it getting free of whatever fetters they place upon it?
This is somewhat of a different take than Eliezer's now-classic 'boxed AI' problem, such as the AI not being superintelligent, and having already demonstrated some aspects of itself by performing highly antisocial activities. However, it does have enough similarities that, perhaps, thinking about one might shed some light on the other.
So: Anyone want to create some further verses for something sung to the tune of 'Drunken Sailor'?
What shall we do with an evil AI?
What shall we do with an evil AI?
What shall we do with an evil AI?
Ear-lie in the future.
Weigh-hay and upgrade ourselves,
Weigh-hay and upgrade ourselves,
Weigh-hay and upgrade ourselves,
Ear-lie in the future.