Really great techniques for pulling brand-similar colors together and building better visual continuity. I would caution though that accessibility-compliance isn’t a silver bullet.
We ran into some issues when following a similar approach to an application and at first glance, the information was legible and pleasing to look at. However, after prolonged use the detail pages resulted in eye fatigue. Our colors were simply too harmonious even at a AAA-compliance rating for contrast and accessibility. Ultimately, we needed colors that were out of harmony with each other to drive an even starker contrast than the standard checks accessibility tools provide. I mainly mention this for sites/apps that have a high density of data and aren’t really geared toward quick browsing.
Just something to consider when doing qualitative testing — understanding the length of time spent with content might be a key consideration as part of this approach. Thanks again for the insights into your techniques, Dennis!