yes, but it doesn't put non-elites ahead of elites, just in the mix with them; its highly unlikely unless the plane is 75%+ elite that they'll run out of space.
True, but it's possible. There's also the possibility that a Kettle buying E+ for a trip months in advance could ace an elite who is buying a last-minute ticket.
The bottom line is UA started the process of "selling" elite perks well before the CO merger.