RE: Shotgun barrel length?
Breach to muzzle.
I's been my experience that, given the same amount of choke, a shorter barrel will pattern very similarly to a longer barrel. I think a lot of people have the notion that the shorter a shotguns barrel is, the wider the pattern will be at any given range (the "sawed-off shotgun"), but that's only true if the shotgun has been shortened without reinstalling a choke system, essentially leaving it cylender bore. Velocity should also not be effected too much either, because shotguns burn moderate amounts of fairly fast burning pistol like powder that is most likely burned up inside the first 12-14" of barrel length.
The biggest thing that barrel length effects if how the shotgun balances and "swings" on birds. I shotgun with a short swings quicker by virtue of less mass sticking out there in front of you, where a longer barrel swings smoother and somewhat slower, allowing one to track a bird and lead it properly by making timing somewhat less critical (or at least easier to accomplish).
If it were me I'd pick a longer barrel for the quail and dove, but not one so long that it interferes in a duck blind...say 26". For turkey, since you aim at a turkey rather than swinging with them as the fly, you can get away with a substancially shorter barrel. In fact, if you look at the purpose built shotguns designed for turkey hunters, you'll usually see that they do have shorter than normal barrels in the 20-24" range. The reason is because such guns are smaller, lighter and more compact and are thus easier and handier in the thick woods, and being shorter there is less relative movement for a turkey to see it you move a little while calling them in. That isn't to say that a 26"+ barrel won't work for turkey hunting, but the shorter barrel is a convienience.