1994 The Treasure of the Bribri Kingdom (The White Snake Gang sends a demon to kidnap Shin)
1995 Unkurosai's Ambition (The samurai Fukisetsukumaru is a woman disguised as a man, and her younger brother is a man disguised as a woman. The final boss is a gay double demon, a pair of sirens)
1997 The Great Pursuit of the Dark Pearls (There are three sirens in the Pearl Yuria Clan, and the demon Jaq has become a siren)
1999 Outbreak! Hot Springs Armageddon (There is a masseuse under Dirt Daren, who resembles a siren)
There may be more in the other theaters, that's all I can remember... Crayon Shin-chan has a surprisingly large number of sirens in it!
2006 Dance! Friends! (There are ballet sirens in it)