You can get hidalgo from MrMunou channel (the ust maker):https://www.youtube.com/user/MrMUNOU#p/a
-It's in vocalochu but there is a mistake with the pasword, it has an extra space at the end.-
But I think it's a song more for a male... and the ust is quite out-sinc from the original karaoke and you have to edit it heavily -_-
How about "Trick and Treat"? It's true you'll need a partner for it but I think it'll fit, heh.
It's in the vocalochu list
But it's true that one goes more to the creepy side and I think you want something more joyful.
"Hello planet" is quite cute. You can find the ust in vocalochu, too.
"Ievan Polka" is another classic. Or "Popipo".
"One sided love samba" is a beautiful song (I love Owata-P works)... but too bad the ust is for VCV and to make it for CV is quite hard.
Well, all those songs are in that vocalochu list. It's an easy place to find premade material.
Also, don't forget to write down who made each ust to give credit later ·_- b