Hi Lisa,
Thank you for raising this query.
Personally, I don't think there is a need for a script here as it's way easier by carrying out the instructions below:
1) Navigate to the firewall's expert mode and type chsh -s /bin/bash admin
The above command should put you in expert mode upon the next login.
2) Then, to display the output of certain commands upon login, you will need to edit the .bashrc file inside the /home/admin directory. Once inside the said directory:
vi .bashrc
Press Shift + G to go to the bottom of the file followed by 'o' to start editing the file.
Next type the commands that you want.
grep admin /etc/passwd
date
Have a look at this screenshot as well if needed:
3) Finally, press Escape followed by :wq to save the changes. The end result can be seen below next time you login:
4) Repeat the same process on every other firewall.
Since you said that you administer only a few firewalls I believe that would suffice.
I hope this helps.