candledave (#9) and loge (#11)
AARRRGH! I was in IT for 25 years and still didn't get that "Twelve"!
All done now, apart from parsing the last three words in 5 down, but I suppose I can mosey over to the "Dark Side" to find the information I need for my forehead-slapping moment.
My heart sank when I read the preamble and saw that jumbles and multiple clues within clues were involved. But once I hit the PDM with the theme, it was a big help with filling in the across entries and reverse-engineering to the answers to the 'cluelets'. (I did something similar with Christmas carols for a church quiz sheet a few years back.)
The endgame was pretty straightforward but very pleasing. Well done, Xanthippe!