I will try and update this thread.
Update:
Alaska call center agent mentioned that I will not be able to purchase additional baggage in online. I can only buy additional baggage at Airport counter when I check-in my bags. I have to pay Emirates baggage fee for additional baggage and Alaska fee will not be applicable.
Last edited by Jack2106; Mar 21, 2019 at 9:38 am
Reason: Provide an update