glojo - the plan to only have one active has been going for a while. I think it was in SDSR but standby to be corrected. Clearly having one carrier is a little bit crap, but better than nothing (imho).
The problem with "which one to fit for cat/trap" is that the general belief before SDSR was that the ships were designed for, but not with cat'n'trap (ie had all the spaces etc) so a conversion would be relatively straightforward and could be done on the first one. It now appears that there were some porkies told, I don't know if that was by the RN or industry but I am sure it was the RAF's fault
. The end result is that the first one may be too far advanced in build for cat'n'trap to be fitted, as there are some "issues", so it may have to happen on the second one. Of course that means that we will have to wait even longer for a carrier capability, which is bad.