Nice song choices, usually the Chord Charts would be a good place to check in but as these versions are pretty different to the regular ones, they probably won't help much.
First thing is to figure out the time signature. If you open the click tracks, that's probably the easiest way, I could tell the all but O Holy Night are 4/4. O Holy night is 6/8 (had to refer to a chart as I find it hard to tell 3/4 from 6/8).
Figure out the BPM by setting a stopwatch for 15 minutes and count the beats, this gave me:
Away in a Manger - 102 @4/4
Noel - 120 (possibly 124) @4/4
O Holy Night - 68 @6/8 timing
Come Thou Long Expected Jesus - 72 @4/4
If you plug that into Ableton and align your grid then you should know for sure after that