One of those lenses is 11-18mm. You'll be all set with this one, or if you can't wait for it to be released, check with B&H or any other retailer to see what your options are on a Minolta mount.

You've got it right - DSLR's do not change focal length of lenses. It's physically impossible - a 50mm lens on a DSLR is a short telephoto; on a full frame 35mm SLR (or something like the Kodak full frame DSLR) it's a normal lens; on a medium format it's a wide angle and on a large format (if you could even find a 50mm) it would be so wide that you could see behind your own ears...

I'm not sure on this - but don't think that DSLR sensors could be any closer to the rear element than film would be in a 35mm SLR. It doesn't appear to be any different (from seeing the sensor when trying to blow dust off it), and the autofocus system isn't calibrated any differently. All of my lenses focus just fine on my DSLR and 35mm SLR. The sensor is smaller than 35mm film (i.e. not full frame) but the same distance back inside the body from the lensmount. And also, the mirror is the same size at least in mine - so it couldn't be moved forward or it would hit the rear element of a lens on it's way up after pressing the shutter release.