Point two is why I'm so disappointed in many of my friends from back when I studied physics who are really into this idea. Like, it's basic thermodynamics, guys! If we want to make agriculture sustainable we should try to break even energy wise, not waste even more with the physical equivalent to more layers of abstraction!
I've read a few times vertical farms use LED that only emit very specific wavelengths. The solar panel on the roof would capture energy on spectrum unused by plants, making the sun light => electric energy => LED light thingy not as bad as it seems intuitively. Is that possible?
Though i'd guess semi transparent solar panels above fields capturing light plants wouldn't use could be even more efficient, if it will ever exist.