Your biggest issue is not what you are doing right or wrong, but your goal is too big to achieve.

You have 4 people but only 2 people can earn. Given that the non-earning are children, it means that your travel will have to be done during holiday travel season. With that in mind, even you have all the points, you may still be able to have difficulties scoring 4 award seats.

Your best solution is to churn both WN card and CSP. With both cards, you should be able to boost 95K RR points at first. However, both cards have a 24-month rotation. It means you can only earn 95K bonus per person for each 24-month.

Then you will need to catch WGA fares as low as possible to reduce your RR points usage. The advantage of RR is it does not have an award "inventory", so virtually all seats are open to grab. The bad thing is during holiday season, WGA fares will be high. It means you will need to spend more RR to get an award.

Since you are not a frequent traveler, other programs in fact work against you (as your focus is redeeming peak season tickets). So there is no point earning something that you have difficulty to redeem.

In your case, since your only hope is on the bonus, you feel free to keep using your existing cards. However, I will suggest to consolidate the Disney card and Marriott after opening the WN and CSP cards.