Aw, thanks Suzanne!
Here's my Vision attempt... It's a wildly speculative "what-if" scenario, and I don't see it happening, but I attempt to stay true to what we've seen in the MCU so far, and incorporate a popular fan theory.
The idea here is that, as a more-grounded, MCU-based alternative to phasing, Vision is based off of the Mk 42, so his "superpower" is to break into individual pieces that can fly around independently and re-assemble. I know, it's not quite the same, but it's the best I could figure out, using pre-existing MCU tech.
The second idea is that when Coulson was resurrected, perhaps SHIELD kept a digital copy of his brain patterns, in a form that Ultron can upload into the Mk 42. In addition, Ultron recreates the faceplate to look like Coulson, using advanced facial animatronics.
The question is why would Ultron do something like that? The only thing I can come up with is that he wants to haunt Tony with a horrible vision
of his former friend, hoping that it induces his PTSD...
That's my best theory for how you would go about incorporating Vision into the MCU, and here's what it might look like: