My band and I came up with a couple of new songs with a new singer that we got about 2 months ago.
After those first couple of practices the singer failed to turn up for the next 5, including one show and so we've decided to find a new singer.

Those music for the songs we wrote was done by us (drums, gat, bass), and the singer came up with vocal melody for one and words for the other. My question is, is it alright for us to still use these songs? Or would we have to find new melody/words when we get a new singer? (from a legal and ethical perspective)