Welcome!
It sounds like you have a two- fold goal-cash for Disney/couch and miles for Delta. The most important rule of churning cards (getting new cards for the welcome bonuses) is to
avoid carrying a balance so if you can do this then please read on! Also, avoid JOINT accounts because if you and your spouse EACH get a card then you've doubled your bonuses...being an "authorized user" often confers NO benefits and can cost both money and an opportunity for a new card.
The benefit of having a spouse also getting cards is you can
prefer (the board mods don't like the "r" word

) your spouse from your cards, earn a bonus from that action and then your spouse can obtain their new card, meet the Minimum Spend Requirement (MSR) and earn their own sign up bonus (SUB).
I'm fairly experienced with Delta so I'll start there.
First, make sure you have Skymiles membership-Delta's frequent flyer club. Second, fiddle with their website to get an idea of how much tickets to Orlando from your home airport will cost in either money or skymiles. Delta values their miles at $0.01 so you can easily convert BUT they don't have a redemption chart so prices will fluctuate. Still, you can get a "rough" estimate for goal setting.
American Express issues the Delta co-branded cards and they'll have peak SUBs two or three times a year. They also have 4 personal cards and 3 business cards (*almost anyone has a "business" if they've sold on craigslist, had a garage sale or other side hustles) and you can acquire up to 5 different credit cards. For example, when my DD was starting out with Amex, she obtained the lowest Delta Amex card-the blue, which has no Annual Fee (AF). Later, she obtained the Delta gold amex ($99 AF). As the benefits of Amex Delta cards increase (from nothing to free checked bag to a companion ticket [not pass as with Southwest] to companion ticket+skyclub access) so do the annual fees. If you want to keep them low then my recommendation would be for both you and your spouse to consider the American Express Delta Gold (personal or if you have a "business" then "business" since that will stay off of your 5/24 record which is important for Chase). The AF is waived for the first year so for $0 if you spend $2000 in the first six months, then you'll earn either 60,000 skymiles (personal) or 50,000 skymiles (business).
***Side note-there are other, more expensive cards such as the American Express Platinum (not Delta) that has an AF of $695 and several small credits and if you spend $6000 in 6 months, you'll earn 80,000--150,000 of their flexible currency (MRs) BUT it's an expensive card up front and requires some hunting to find the higher earning SUB (sign up bonus). Also, American Express passes on a fee so to transfer from MRs to Skymiles will cost you anything from $0.06-$99, and that puts off some people (not me, I transfer regularly but I also go through skymiles quickly!).
For straight up cash for Disney, one of the easiest family of cards is the Chase family. Chase bank requires you have only received/signed up for 5 personal credit cards OF ANY TYPE FROM ANY BANK in the past 24 months-the infamous 5/24 rule-which requires some strategizing (getting business cards, spacing out applications, having your "P2" aka spouse, adult children, other trusted people acquiring cards). That said, due to the 5/24 rule, most recommend looking at Chase's line up and obtaining those cards first.
The most popular are the Chase Sapphire Reserve (CSR) and Preferred (CSP), which earn Ultimate Rewards which can be transferred to hotel and airline partners (sadly
not Delta, however). These rewards can also be transferred to cold hard cash and/or used in the Chase travel portal (I do not recommend, having been burned but others do use it and haven't so YMMV).
The CSP has a $95 AF (not waived) and after $4000 spend in 3 months, earns 60,000 UR (aka worth $600 in cold hard cash or $505 after the AF is paid). The CSR is more expensive-$550 AF but after a $4000 spend in 3 months earns 80,000 UR plus there's a $300 annual travel credit which is very easily used (pay for a ticket with the CSR and $300 is automatically subtracted from your bill). There are pros/cons to both cards and you can easily google CSR or CSP and read lots more about it.
That said, I might just get one (and then
prefer your P2 to the same card) of Chase's Freedom cards-either the Flex or Unlimited. They both have NO Annual Fee, and after $500 spend in 3 months earn $200 back . The Freedom also has 5% back on groceries up to $12000 spend the first year (so a potential of an extra $600 spend if y'all buy groceries from stores other than
WalMart or Target).
Here's a good chart-
https://creditcards.chase.com/all-credit-cards?iCELL=61HT&jp_ltg=brwscate_allcards
Citi has a double cash that earns 2% back and Discover has rotating cash back categories but currently neither have SUBs. American Express also has some cash back cards but their SUBs aren't as generous as Chase's right now.
I'm sure other people can chime in on cash back options but sticking with 1 or 2 banks is probably the safest plan for now.
Before applying for anything, I'd recommend you and your spouse (P2) sit down and make a list of goals and discuss pros/cons of the cards I've mentioned (or anyone else does). Please feel free to ask questions here--usually we're a fairly chatty bunch.