Hello - earlier this year, my wife and I each had enough miles in our UA account to book tickets to Hawaii (leaving next month). We paid our fee ($5 each I believe) to book the tickets with a Amex or Chase Sapphire card (don't remember). Last week, I signed up for the UA Visa card which states I, and my traveling partner get a free bag at check-in...with a paid ticket.

Questions I have are:
1) What are the chances UAL will waive the checked bag fee since we now have the Explorer card even though we paid for the ticket using miles, plus the fee with another credit card?

2) What is the process to pay for the bags since for this (or future) trips? Last time I flew with UAL (2 years back), I checked and paid for our bags online the night before for a small discount. How does this work if you have the Explorer card? Does UAL credit the account for the baggage fees? Do we not check our bags online, and instead just show my Explorer credit card at the ticket check-in counter for the waiver?

Thanks in advance for your replies...
Ray