Adorable! It isn't a good idea to mix birds of different species and clutches in one brooder. Disease can be a concern (since few breeders disease test everything), and they also bring a new biome into contact with the other babies with really immature (and therefore weak) immune systems. The scarlet is quite a bit older and is likely flapping (as it is fledging age) and disturbing the other residents. Likely won't be an issue, but since I always try to point out best practices, I figured it was worth a mention in case someone reading this one day wants to breed.
Fun you are getting lots of pics, it is only few times in one's life we get to go through the experience of getting a new pet. It is great to share the growth to make your clients have the most exiting experience you can offer.
Adorable face on him!