You will be fine without the purchase of EBCI. The only time I purchase it is when I know I won't be able to check-in at the 24 hour mark (like on a cruise).
I disagree that is a necessity to purchase. I fly with a party of 3 all the time and we have never had an instance that we didn't get an entire row together.
As a party of two, you will most likely find seats before the exit row together and if you don't mind splitting up, you could be in the first few rows.
Just set the alarm on your phone to remind you to check in at 24. Make sure you have your confirmation (reservation) number with you. Once checked in you will get a boarding pass with a letter (a,b or c) and a number.
Once you are at your gate, you will see poles with numbers: 1-5, 6-10 etc.
When your group (a,b or c) is called to line up, you just go to stand where your number is. If you are late to the airport and your group has already gone, you can go up anytime.