The handlebar bag that I usually use for touring has green side pockets, some black and some white. Use that with my yellow Ortlieb panniers.

Your mix of colors might make it a bit more theft proof. I usually think that thieves are opportunists and I assume their eyes are drawn to something that looks nice. That is why I never clean my bike on a tour. I assume something that looks less attractive is more theft proof.

If you have enough steerer tube to fit a second stem, you might want to consider that as an option for your new bar bag. It lowers the bag and brings it a bit closer to the steering axis if you use a really short stem. But it since you take a smaller size frame than I do, your bars are closer to your wheel than mine so I am not sure if it would be as much of an advantage for you as for me. Some photos of some of my bikes showing the second stem at this link:
Help with handlebar bag and rack selection