I did some more digging. I found these stealer logs which show that the shooter had a Roblox account with the same username "Craftin247":
The email
21robintyl@washk12.org had some breaches, but
@Spectate did not upload them so I will. I attached them in this post.
From the Facepunch breach, this IP address 74.211.29.167 led me to another email:
fualad@yahoo.com.
This email had a lot of breaches, including being in Stealer Logs, which I believe is his. The Microsoft account is created in 2016, which is the same date the other school email account that is linked to Tyler Robinson.
Checking the breaches reveals these emails:
In the Crimecraft breach, I am not sure if this email is his or belongs to a family members. Checking it reveals it also has a Napster account, which was more popular in the 2000s. I think this is a family members for that reason.
The other IP address of which the accounts had breaches, belonged to another person who also lives in Salt Lake City, Utah. It is not a family members or linked to him, as it had someone else's full legal name in that email. This person also had a vastly different name scheme, and was in The Post Millennial, further proving this theory.