A lot of them were pretty reminiscent of the spells from Zelda 2. It's interesting how much Ocarina takes from Zelda 2, with all of the sages being named for the villages in Zelda 2 (minus Mido since he was cut as a sage in favor of Saria) and Impa since, y'know, its Impa. 
Regarding the songs though, you were originally supposed to slot the Spiritual Stones into the Ocarina of Time in order to power it up. The original Spiritual Stones were designed to look like bits of music notation and had little holes you'd socket them into on the ocarina. I guess they decided getting the lame ass Fairy Ocarina was more important.