-EVOLVED POWER ADAPTATION: At the beginning of your turn or after resolutions when Amazo takes damage, you may choose a standard power that a character within range and line of fire can use. If Amazo is 290 points, you may choose an additional character and another standard power that character can use.

So can Amazo choose the same character when you play him at 290 points? I am wondering what the "additional character" refers to. A different character or can you choose the same character different power.

Second power steal comes from a new target fig if you can see it. That's the way it reads to me. I guess the "evolution" is that he's mixing and matching different super heroes instead of one power set from Flash or Superman for example.

That is my take as well.

Might be wrong, maybe there is some official clarification, but Amazo needs that second target to get a second power.