As far as water bottle holders go Ortlieb's add on water bottle holder for Ortlieb panniers seemed a little funky at first. But it works well for bottles and more importantly for my JBL Charge speaker.
The Ortleib water holder mounted on my Ortlieb front rider pannier.
I like using the small panniers when I ride my ICE Sprint so I can carry more stuff on longer rides.
My JBL Charge in the water bottle holder.The water bottle holder consists of three straps that have to be connected at the back of the holder. The JBL Charge usually fits in most frame mounted water bottle holders but it's a little too big for the Ortleib holder. The center strap of the Ortlieb holder is a little tighter then the top and bottom straps. I leave one side of the center strap unconnected to accommodate the speaker. Even without the center strapped connected the speaker remains firmly in place.
Closeup of the Ortlieb water bottle holder. The center strap on the opposite is left unconnected to allow for the JBL Charge to slip in. When the center strap is connected on both sides it creates a pressure ring that keeps a water bottle from bouncing out.