Thanks Boydie and tone, some great advice and info there!
To clarify further the songs are intended to be recorded by other artists, however they are finished masters, not demos, so could also go into libraries. From your advice and from advice from another forum, I think the best plan is to try to scare up some interest from publishers/artists/ managers/producers before commuting them to any exclusive or in perpetuity libraries?
Say we were to place the songs in non exclusive and non in perpetuity libraries and they were actually used in various media. Would this encourage or discourage a perspective publisher?