It will be hard to meet your objectives, but you're providing all the data, and that helps. AA is really your only choice because DL has very poor international award availability. The UA and DL miles will realistically not be very usable.

You can sign up for a number of promotional offers from time to time to help get miles. AA has a diners AAdvantage that gives points for restaurants. There are banks that give points for signup and balances. The best way to find out about all those is to go online to AA.com and look up all the ways to earn miles. That will help a lot. Then you need to examine your strategy.

AA does not permit family members miles to join in one account. Another One Wrold carrier British Airways, does. You can have your parents join and those miles will be far more than you otherwise might get. That, however, has fewer ancillary earning choices, but all your AA miles can apply. Check that one at BA website.

Good luck!