Hello, I already completed (from my perspective) the challenge related to this task, I am attaching screenshots of my results in two different attempts
Attempt 1
In the attempt 1, I only created the ssh keys for each user and host combination (tony - stapp01, steve - stapp02, banner - stapp03) and added in the remote servers the public keys. Also, I added the private keys to the ssh agent and verified the password-less login for user and host.
Attempt 2
In the attempt 2, I did the same as in the attempt 1, and additionally I modified the .bashrc file to enable the ssh agent and added all the 3 public keys. To verify that, I check the ssh login with no password in the current terminal and opened a new one to verify the ssh agent and the public keys were added on login for the thor user.
The activity is under a fail state and I don not know why, the ssh login for each sudo user is activated in the remote hosts and the ssh agent and the public keys are explicitly added at login for thor user in the .bashrc file
PS: I had to put all the screenshots in one, due to the limitations of the post, etc . . .