You are considering two zoom lenses that overlap with your existing zoom lens. If you go ahead with these zoom lenses, you woud be better off to sale your original lenses.
However another approach could be to consider some prime lenses instead of zoom lenses. Pentax has some superb prime lenses: the DA Ltd series, the FA Ltd series for example. The sharpness and IQ of these prime lenses are superb and you shoud consider a couple of prime lenses. Even possibly some fast primes with large aperture (low f).
There are also some nice 3rd party zoom and prime lenses not to ignore.
Based upon my own, limited experience, I would suggest to consider the FA31mm f1.8 Ltd, a superb prime with the highest score in the in-depth reviews of this forum.
Food for thoughts,,,