You will want your front stage speakers to match, tonally at least. The surrounds don't really matter as much. You just don't want a wild tonal mismatch with the fronts. The good news is that the Paradigm Premiers have a neutral tonality, so anything that aims for a flattish response will be a good match. So don't spend a lot on bookshelf speaker surrounds.
For bookshelf speaker surrounds, I would be looking at some
Ascend CBM-170s as a less expensive alternative to the Paradigm Premier bookshelf speakers. I think some
NHT C1s would also work well. I think KEF Q150s would also be good too.
As Mazer said, it doesn't matter at all for subs to match.