Just happened to pass by and saw that X and Y are open. You don't have to use mine (but I am so glad that you put down the other ones that I put down previously...so thanks!), but I have ideas for them:
X- X-ray [Prussia/Austria]
Y- "You Make Me Feel" (Cobra Starship song) [US/UK]

P.S. Good luck with the Alphabet Meme. XD