Yes, although training a flight attendant* to land a plane then expecting to pay her like a flight attendant isn't exactly tenable.
Expecting any standing passengers to survive a crash is highly unrealistic, even with vertical seats -- which is why that idea is negligent at best.
In this case, regulations exist for preventing corporations from reducing prices--that, even while more people might fly--come at too high an external cost.
All three ideas are absurd. An autopilot seeks to automate the majority of cruising tasks, but it's yet another computer system with garbage in, garbage out. The existence of a redundant individual seeks to act as the equivalent of the triple or quadruple-redundant computers in place on the aircraft. In the general aviation world, the presence of a second pilot greatly increases safety. Not only would standing be tiring, it would prevent people from having a crumple zone underneath them (the seats look like they can collapse for a reason -- they do) and greatly increase crash mortality. Allowing flight attendants to land planes just seems a bit silly.
Startlingly enough, propelling a can of people through the air is still pretty expensive. You can only do it so cheaply, especially with an acceptable level of safety.