Wow, that was quite a downpour!
Hard to say how they’ll sound with your JBLs...they are pretty different types of speakers. But it won’t cost a thing to try!
When I added my ceiling speakers recently, and ran through the Audyssey setup, there was a big difference in the sound of the test signal when it hit the ceiling speakers. My setup started with a 5.1 matched set and I added another set of mains for my surrounds and moved the original surrounds to the rear. The Audyssey sweep signal sounds very similar through those 7 speakers, but the ceiling speakers were quieter and muffled compared to the others. Ok, Audyssey will EQ those speakers for a flatter response at the MLP but how can an amp deal with different speaker sensitivities? I don’t think the test sweep is checking/adjusting dB levels across multiple input levels. So it seems that you could have a volume balance issue with different unmatched speakers.
Looking at the specs of your JBL vs Klipsch speakers, the sensitivity ratings are 91 and 94 dB. Now add the horn tweeters on the Klipsch and I can easily believe they’ll sound brighter and louder than the JBLs. But again, it won’t cost a thing to try!
I hope they sound great!