Tanager 20 CFL

Yeah, basically. I have the Feathered friends tanager that's a zipperless sleeping bag, and the Cumulus Aerial 180 (similar to the model you're asking about, but lighter/no hood). Can't fold open like a quilt, but no zipper means less weight, and being totally enclosed means no drafts. I sleep cold, so I rarely would want to stick a foot out of a quilt or open it up, and the false bottom saves weight. All comes down to preferences. With the Tanager and Aerial, I've never minded wiggling in/out, but YMMV.

I backpack with my 9 and 6 year old boys. Last summer, I had them both in 12L REI Tarn packs that I picked up on Facebook marketplace for like $40 combined. They use 8 and 6 sections of Z lite foam pad. I bring quilts for them, one of which is an old 28 oz 10 degree EE quilt from when I first went ultralight, and the other is a Feathered Friends hoodless sleeping bag that I bought for basically half price on Facebook marketplace this off season. Just make sure to bring a warm beanie for the kiddo to keep his head warm. 18L is about the most volume I would recommend in a pack for a 5 year old. You’ll want the pack light and small enough that you can easily carry it in an extra hand if he gets tired of wearing it. The torso size (assuming the pack has a hipbelt) is one of the more important factors at that age. Ideally, you’ll want a pack with an adjustable torso length, th shorter the better at his height. My 4’4 9 year old has about a 12-13” torso measurement for reference, but it’s easy to measure. Bottom line, you’ll end up with some extra weight and volume in your pack in order to make the experience better for him. I

Feathered friends will customize bag sizes. At 950 fill power down they are as lightweight as you can reasonably get.

The ratings are not always reliable so you are right to be uncomfortable with them. One good baseline is ounces of down at the same fill power. Comparing bags that way gives you a better comparison point. Western Mountaineering and Feathered Friends are generally reliable in their ratings. That should give you an excellent place to start.

Feathered Friends will customize bags. They did it for me.

Western Mountaineering, Feathered Friends or Marmot for bags. Enlightened Equipment, Hammock Gear or Katabatic for backpacking quilts. Not cheap but quality and comfortable.

I've been a quilt user for years, but if I were looking for sleeping bags, I would go with either Western Mountaineering or Feathered Friends. You absolutely get what you pay for with either brand. Awesome quality.

I have some Feathered Friends bags. They typically come with a stuff sack larger than how small they could pack (in fact they can easily be compressed at least another 30-40%), and that stuff sack size generally seems to vary across manufacturers. Should you compress it more? Debatable. But you can.