Step Away From The Karaoke Song Book

It's Christmas!!!! so shouted Noddy Holder and plenty of people over the next few weeks as Christmas and karaoke season combine in a cacophony of awfully mutilated Christmas songs but luckily my blog partner knows a Classically trained singer and she really does have the voice to make kittens cry so we asked her which songs should someone who sounds like a donkey braying into a bucket fire up on the Christmas Party Karaoke machine and which ones should we not touch with a ten foot candy cane?    
In her expert opinion the easiest Christmas songs to pick are Last Christmas, It's Beginning To Look A Lot Like Christmas, Have Yourself A Merry Little Christmas and Feliz Navidad because those songs do not contain much variation or vocal acrobatics so as long as you start in the right key, you should be fine to stumble your way through them and not have people talking about your performance until next August.
So which ones should be avoided like a patch of yellow snow? Her top five that nobody who hasn't been trained should attempt are firstly 'Silent Night' because this song has much dipping between a low and high register and often within the same short phrase and without much space to pause for breath.
'Carol of the Bells' is performed in a minor key and needs at least two people who have to be perfectly timed with all that melodic chanting offset by foreboding notes and vocal imitations of bells so that should be a firm no regardless of how much Jägermeister you have drunk.
Next one up is 'Angels We Have Heard on High' as it  has one of the most technically demanding choruses of all the Christmas songs with the repeated 'Gloria in excelsis Deo' lyric having to be sustained over a long sequence of fluctuating notes which is merciless on the lungs unless you can breathe like a professional singer, which you can't so stay away from it.
'O Holy Night' is a beautiful song but a real test for anyone's vocal range with both lows and low lows, highs and high highs, octave jumps and sustaining notes as well as conveying emotion so definitely the one most likely to have you pulling a muscle.
Also on the list and the one to be absolutely fenced off is 'All I Want for Christmas Is You' which our friend says should come with a Health Warning to karaoke singers with it's soaring high notes and switches across the whole of Mariah Carey's full five octaves which is one more than most female singers are capable of which is why nobody but Mariah should even consider attempting it, and even most professional singers don't so you tanked up in a pub after warming up by singing in the shower because you are not going to do anything but suck at it.
She then gave a short burst of Silent Night which really did make Tiddles cry and i replied with a short burst of Glor....or.....or....or.....or....oria, which made her cry.