Hi BGMatt -- I'm not a poultryman, just a hobbyist so others here may have more valuable input on the breeds you've listed, but I'll add my two cents on the breeds close to my heart.
Over the past dozen years of raising chickens, I've developed a list of desirable qualities: 1) Temperament must be stable. No aggressive males (or females) particularly with small children, 2) Egg laying - they must produce sufficient quantities of eggs during the appropriate times of year. A winter hiatus is acceptable though we select for late and early season layers, 3) Hardiness. I don't pamper my poultry. They must be willing and able to forage for at least 50% of their diet (no parking in front of the feeder), have predator savy, be able to thrive in our climate of wet winter cold and high summer heat/humidity, and last, but not least, with all the work involved raising chickens, I have to enjoy them - watching them, working around them and handling them. As for aesthetics, I personally like crests, patterns, rich coloration and unique characteristics. And like you, I want to put my efforts into preserving the uncommon or perhaps unpopular.
One of my favorite breeds is the Houdan. They really need help. So few people are working with them, and truly, with the limited (mainly hatchery) gene pool, it may not even be possible to bring them back to what they were without the hassles and expense of importing new stock from France. I was lucky enough to get some from Mr. Urch who doesn't breed many of them and doesn't even list them as availble. It's a real shame, they are such a great chicken. My Houdi (rooster/cock bird) would have been named Charlie Chaplin if his original place holder name hadn't stuck. He is such a comedian. Coming home at the end of a hard day at work to see him up to his antics with the girls just puts a smile on my face. I'm trying to do my part to make sure this breed doesn't disappear altogether.
I also raise Langshan, one of the breeds on your list. I like the Black and the White, Blue is fairly recent (per APA acceptance.) I haven't eaten any yet as I'm still growing my flock and working on type, but egg production is pretty good. They also do great here in Virginia. While all of the other chickens were huddled on any non-snow covered surface they could find on a 16 degree winter day (thankfully not too common here) the Langshan were out there foraging in the snow like it was just some minor annoyance in their search for tasty grub. In summer, they are smart enough to seek shady areas to rest during the day. They are also (to my eyes) a handsome and regal looking chicken.
I too have been doing some research on the Rose Comb Rhode Island Reds but can't offer much input other than I WANT SOME!

Stunning looking birds, and they too seem to need preservation.