No. 7-X hasn't performed any fusion at all and while they later want to use plasmas that are closer in composition to what you'd find in a fusion reactor, very little fusion will take place — intentionally, to avoid generating significant amounts of neutron radiation.
It's perhaps important to point out that fusion is not difficult; it's very easy in fact. The hard part for power generation is plasma physics, i.e. being able to contain and control a plasma effectively. That's what 7-X is designed to research. If you can control a sustained plasma, fusion power is relatively easy.
Yes it has. It hasn’t broken energy breakeven but fusion is definitely happening in that plasma and, for that matter, plasmas at lower temperatures, lower densities and with lower confinement times. Getting particles to fuse is pretty trivial.
He was an inventor of a variety of television technology, and I believe the designs were very similar to his fusor. Unfortunately, the design cannot be made "exothermic" IIRC, and the research ruined him financially.
I am no plasma physicist, but the concern I hear about fusion is that whenever we scale a system up we find the plasma is behaving in new ways, resulting in new loss mechanisms.
Identifying and understanding those new behaviours sounds more like science than engineering to me. (That said, scientists frequently do engineering and engineers frequently do science; I've been on both sides of it).
It's perhaps important to point out that fusion is not difficult; it's very easy in fact. The hard part for power generation is plasma physics, i.e. being able to contain and control a plasma effectively. That's what 7-X is designed to research. If you can control a sustained plasma, fusion power is relatively easy.