I think the southwest companion deal would work for you. One of you, either you or hour partner, needs to sign up for 2 southwest cards that will net bonus & accumulated points totaling 110K points. Then you can use the points to get one ticket and the companion pass to get the other for free. I think min. spend on these cards is maybe 2K per card, so you should be able to get close with your 3-4K in spend.
If you will be handing $$ over to Disney resorts for the trip or park tickets, look into a disney vacation account. It doesn't yield any interest, but for every $1K you spend on your trip, you'll get a $20 gift card. You need to establish the account x months before you can get the bonus, so look into details... Yes, $20 is not a huge bonus, but a 2% bonus is more than what most savings accounts yield. Another advantage is accelerating spend to meet bonus requirements. You can "contribute" to the DVA using a credit card. DH and I used the DVA to help meet minimum spend requirements on a couple of cards late last year, but we don't plan on taking the family until early 2018. And you can always get your $ back if you decide not to use the DVA funds for a disney vacation. says the terms and conditions. I haven't tried it, since we actually plan on going.