In reply to konrad7272:
> For the suggestions of just climbing the first pitch - our outdoor experience so far has only been in places that have lower off anchors that we can thread through and lower off - my understanding is that at the end of the first pitch of a multipitch there wouldn't be those lower off bolts. Is this correct?
In most cases, the belays are likely to be rigged for abseil hence they will have threadable lower-offs at the top of the first pitch.
Having said that, I am wondering if something is going slightly wrong in your search. There are in fact FAR more single-pitch routes under 6b in the Costa Blanca than multi-pitch. Are you interpreting the fact that the crag has a multi-pitch icon as meaning that all the routes at that crag are multi-pitch? If so then that isn't correct, it just means that the crag has some multi-pitch routes (perhaps a lack of clarity in the symbol there).
A helpful document for you could be the PDF intro for the book which has a useful table on page 40. You can download this here - https://rockfax.com/wp-content/uploads/intros/costa-blanca-intro.pdf
(This is something we would like to include in the app but haven't yet figured out a place for it).
Alan