I expect it would take them all, but Earth is by far the easiest for it to start with. I don't see why it would leave anything for us unless we'd successfully instilled it with an interest in doing so, but that won't happen by mere chance and luck.
The SSE might consider to keep humanity around as a "backup" to reinstate itself in case something unexpected goes horribly wrong. For example, a strong solar flare might destroy the SSE (or at least critical parts of its infrastructure), or a non-earth SSE could feel threatened by the earth-SSE and wipe it out, while ignoring the harmless humans, who then rebuild the SSE. Diversity makes for more robust systems.
And there is also the reason for why I keep all this trash around in my house instead of throwing it away. The odds that I'll ever need it are pretty slim, but if I should need it, it would be a hassle to reacquire, and it costs me almost nothing to keep it around.
The SSE might consider to keep humanity around as a "backup" to reinstate itself in case something unexpected goes horribly wrong. For example, a strong solar flare might destroy the SSE (or at least critical parts of its infrastructure), or a non-earth SSE could feel threatened by the earth-SSE and wipe it out, while ignoring the harmless humans, who then rebuild the SSE. Diversity makes for more robust systems.
And there is also the reason for why I keep all this trash around in my house instead of throwing it away. The odds that I'll ever need it are pretty slim, but if I should need it, it would be a hassle to reacquire, and it costs me almost nothing to keep it around.