I've used a bucket spigot and a hose instead of a racking cane and siphon to transfer to kegs before. In theory, in terms of oxidation risk, it should be no worse than a siphon. In practice, I found the spigot clogged easily, and I think that more yeast material was transferred than would have been with a proper siphon.
With respect to using a bucket as a secondary, I would think a carboy would be better due to reduced headspace (and therefore less O2 available). If your beer is still off-gassing enough CO2, it may not matter. Most of the time when I'm racking, I purge the container with a CO2 bottle to try and displace as much free molecular O2 as possible. Probably unnecessary overkill, but it certainly can do no harm.
As I said, I do not often use a secondary (with beer, mead is a different story). I don't have a problem with leaving an ale in the primary for a couple of months, if I wanted to bulk condition much longer, I rack it to a keg or would use a secondary. I personally feel that there's more risk from oxidation due to siphoning mishaps / errors than there is to autolysis - if that's your motivation for moving to a secondary. It's my thought that excessive headspace in the secondary is less of a risk than the actual racking process - there's a potential for a hell of a lot more surface exposure to O2 during racking, and the amount of available O2 is for all purposes unlimited. So I make a point to only use a secondary when I have a compelling reason to.
Just my opinion, and subject to change if compelling evidence to the contrary is given.