+i for Bluemels, but they're so hard to find and pretty fragile to boot. Leave them for some nut who are trying to go period-correct on a 1948 Raleigh Record Ace.

+1 for white, but I doubt you're going to find Cascadias in white. I found a different model Planet Bike fender in white a few years ago, and haven't seen another pair since then. Off-white is good too, should you find it. If that tan counts as off-white, it might be good. I can't tell from the photos.

But wait. You did such a nice job on the frame, couldn't you spray paint a pair of fenders? I know painting plastics is an iffy business, but I'd research which kind of fenders take paint best, and go with those. Primed and painted.