You've got a point. It might just be coincidence that the two powers I have possess similarities to his. I am sure there is another Stand User out there who has some kind of electric based power. I wouldn't say the shocks really feel like Hamon anyway. It's much less controlled.

[Which might just be his fault or it might be the fault of whatever is going on. Who knows?]

There have to be more variations. If his older self was in the city, there might be reason to specifically mimic Joseph, but he's not. There's no point in mimicking powers that he is only going to vaguely recognize if he does at all.