Don't buy the bundle. It's not necessary. Depending upon how you look at it, it's either poor software development, failing to check the bundle contents against your actual ticket, or it's an outright deceptive business process, hoping you'll buy something you already have.

You'll have no problem accessing the lounge at IAH in both directions, and EZE on your return flight only. And the club pass they're selling you wouldn't get you access on arrival at EZE anyway.