Hi!
As per IRCC, if you’re applying under the EHCW stream, the profession should be listed in Annex A only. It should not be combined with other essential occupations. As a proof of employment, you must attach employment letter stating your duties and that your job profile matches claimed NOC under Annex A. You must attach all paystubs that shows that you worked a total of 1560 hours in a given 1 year period prior applying for PR.
Also, you have to attach proof(s) of your travel history, address history, and employment so in my opinion, attaching all paystubs is not going to hurt. Again, attaching t4 is not going to hurt your case. Just give an explanation that you attached your t4s as well.
I hope that helps. Goodluck to you and your friend.