That's probably only a concern if you'd use Jupiter as resource.

I think they are plausible, but the real challenges lie more in the technology, logistics and perhaps more importantly the time-scale. Dismantling an entire planet for resources is going to take some wicked technology (mostly in space-faring and -hauling capability) but above all a really long time. The creation of the panels is probably trivial when we can dismantle a planet, but placing them where we need them is going to take a hell of a lot of time again, simply because of the vastness of space. I'd guess completion of a dyson sphere would take in the order of a few 1,000 years.