You do know that regular economy tickets include a checked bag on AA tickets to Europe? If you’re booking Basic Economy know you possibly won’t be seated together or run the math on paying the fee to select your seat and then decide if the cc for free bags is for you.
As far as miles go that’s a lot more complicated for 5 people. If that’s a path you’re interested in come ask on I love credit cards. You’ll potentially need 1-2 years of lead time and will need a flexible schedule (like not traveling over holidays, school breaks, special events).