It doesn't look like the Z612 can use AA batteries, just the lithium-ion block type.
Now, what exactly are you looking for in a camera? Of the four you have listed, they seem to range from a basic point and shoot to a decent professional model. The price, too, seems to vary from $230 to $499. With a price range you're willing to spend in, plus a little detail as to what you want in a camera, we can give a lot better advice.
Now, since you said you have 4GB worth of SD cards, then I would recommend this
Kodak Z650. It has the same megapixel rating, 10x optical zoom, and no image stabilization. But, it can take both lithium-ion block and AA batteries, and uses SD cards all for a hundred dollars less than the Z612. It might be worth considering.
Jam it back in, in the dark.
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Sol