A couple of questions (with pictures)

[sorraia]

Do you know approximately how old the male and female were? Having them both die unexpectedly is alarming, however if the female did die due to birthing complications or an infection, that is not necessarily something that will affect the weaned babies.

Having said that... I am not aware of any ways to tell recessive blazes from dominant blazes, other than to look at markings as a whole and know the bloodlines the rats came from. If you don't know bloodlines, you'll have to rely on markings. Looking at the pictures, I personally don't see anything that screams dominant spotting. They look to me like fairly typical H-locus markings. Test breeding for blazing isn't going to be reliable either, because if the blazing is recessive, you'll need to be sure your test cross does NOT carry the recessive gene. If any of the animals in the group have blazing or head spots, there's a good chance some of the non-blazed animals carry the gene, so test mating won't be reliable. The biggest concern with the dominant spotting is megacolon, which you should see signs of. You'll need to look for failure to thrive (smaller, thinner than normal), lethargy, appetite disturbances, constipation, unusual stools (massive watery stools instead of normal pellets), and bloat. I don't see the thinning fur you are describing, so I'm inclined to think that may just be moulting. If any of the babies are rex (looks like one might be), that alone would explain the thinning fur (rex are NOTORIOUS for thin fur, especially when moulting, and especially as they age).

As for colors...
First guy is beige. His color does look light, but that may be due to age, or he may carry other recessives that are lightening it. The darker eyes indicate beige instead of champagne, which would have pink/red eyes.

The blaze pictured with the beige is an agouti.

Next one is indeed American blue.

The picture of the agouti girl actually makes her look like a grayed cinnamon (mink + agouti), or maybe a Russian Blue agouti. It's harder to tell since you say the photo makes her look more brown than she truly is. I would say she definitely has something else going on with the agouti though. I'm inclined to say Blue or Russian Blue.