I'm so sorry to hear about your chins, that is horrible.
It seems to be a bit split on who you ask, in the pet chin world Oxbow, Mazuri, and Science Selective seem to be the recommended ones currently. With Oxbow though they now have a couple other formulas but only the Oxbow Essentials is recommended the other two aren't good. People that have a lot of chins, like breeders, still seem to go with the rabbit food, likely because it's cheaper and "close enough".
Unfortunately there is still no actual research done on not feeding fruits and veggies. I think the problem is the people that have the number of chins needed for a proper study would be the large scale breeders, and since they just feed plain pellets, hay, and water and have had no issues they aren't going to be motivated to look into other diets, especially when the study is just to prove they aren't good. When you have people with chins living into their teens and
20s on just a simple diet that seems to be proof that extra stuff is not required, but I know some vets wont see it that way. There was also a thread talking about this recently
Vets Recommend Fresh Greens
The Ferret and Critter Nations are still the most popular cages, but they are not the old 142 and 242 models, what you can buy now are the newer "no tools required" snap together FN 181 (single)/182 (double) and CN 161 (single)/162 (double). The two cages can also be mixed and matched, they are the same size so they fit together which can work out well if you need two different kinds like for a kit or if you have other animals and want smaller spacing on the bottom unit. There are still a lot of vendors that sell fleece for them, most people use Etsy now.
The Blue Cloud mine closed about 10 years ago, so with the exception of finding old stock someone is selling you can't get it anymore. The mine that has taken over for it is Blue Beauty, which is in the same mountain range area but different mountain and is where companies like Oxbow and Lixit get their dust now. It's not exactly the same, it's a bit more sparkle to it then the blue cloud had but I haven't had any issues. The new "best" dust if you are in the US now is ChillDust
ChillDust: Premium Bathing Dust for Chinchillas and Degus it is only sold online and in the US though, which is why I haven't tried it myself (shipping to Canada would cost more then the dust, lol). I would just steer clear of the Kaytee dust, there have been a lot of issues with chins getting skin, eye, and respiratory issues with that dust.