My opinion and experiences with such are this.
Over my own CQUK Coated Tahoe which was done a good three years ago, and at present have no ability to re-correct, and re-apply CQuartz, throughout these past few years I've used a few number of what were said to be acceptable products to help maintain the coating, and hopefully make it last as long as possible.
Overall, I've been very happy with the results and protection CQUK provided me. But like anything, it's not going to last forever, so.
I've commonly used Carpro Reload, from as soon as an hour after CQUK application and for the next following 2 years, nothing else applied.
At about the 2 year mark I decided to buy and try GTechniq C2V3 as a topper. Worked OK, similar in many regards to Reload I thought, and figure is seemed to last about the same length of time as well. Maybe two months.
Then most recently I bought both Blackfire Coating Booster, and SiO2 Spray. And I've tried them both. Again I suspected a similar time frame of longevity, looks, and other properties like Reload-C2V3, and I seem to be correct. That these types of products were not designed to be highly durable, just bring back some of the fresh qualities of a Ceramic Coating.
SiO2 Spray that I tried seemed to be quite "weak", a watery product, and upon just doing only part of the Hood, I stopped right there.
I turned around, and grabbed a bottle of IW-845 and applied. After I applied, removed and felt and inspected the paint, again felt the rock hard turtle shell finish that now was there, and the assurance that I've known for literal decades about what Collinite products can do, I had a great big smile on my face and said these words to myself....
"Now I know I got something on the paint!" The next two words were "Oh yeah!"
I look at it like this. If these Paint Coatings are as durable as they claim to be, then I would say there's no fear of using a product like Colly IW over them and having it remove or damage a underlying Ceramic Coating.
As for Hydrophobic Qualities, I would say Colly #845 is no slouch in this regard, as all who've used #845, I'm sure you've been wowed by the insane Beading, that looks to me as good as CQUK, and probably any other Coating product on the market.
When I was applying the #845 with a Meg's Foam Applicator, I could feel that product literally cutting through grime, probably Tree Sap as well, and other Road Grime nasties. The Paint initially felt like Sandpaper.
It was crud that none of those other products I mention above even slightly touched or removed.
When I got through, the paint felt as smooth as if I just Clayed the Truck. And it glowed, very impressive, love you Collinite! Bravo!
With all I've said, I really see no harm-foul in the combination of such products. In fact it might be a very favorable 1-2 punch to maintain and protect the paint