I love this idea! I think you should do it! Because if not now, when?
All of the current issues seem to minimize your particular weaknesses (small children, minimal entertainment that a small child won't care about, first time visit) while maximizing your strengths (low Covid crowds, cheap travel, good weather in late winter, etc.).
And you've already received some very valuable advice here in this thread from others in tune with your particular young family demographic. That said, I will offer up my unique advice from the perspective of a Disneyland expert. Ready?
WDW is big, and it's not efficient. You'll need to get used to waiting around for buses and long commutes on not-so-efficient mass transit that seemed cool in the 1970's but hasn't aged well. Get your mind ready for a long morning commute and a similarly long evening commute back to the hotel, and you'll be fine. Don't expect speediness, or efficiency. You are on vacation, so just try and slow down and don't expect crispness or professionalism from the WDW CM's who are in charge of the various transportation systems. If a random WDW CM somehow summons up some crispness or professionalism, consider it a fun bonus!
There used to be a whole science behind this. But now, in the age of Covid, who knows? I wouldn't worry about it, but realize that the first park people want to see is Magic Kingdom, then Epcot, then the other two.
I would plan for two days in Magic Kingdom. Not only because it has the most to do of any WDW park, but is about the same as DCA in comparison for things to do, but also because it's a fun compare/contrast that will make you exceptionally thankful for Disneyland once you get home. My second choice for a second day is Epcot, because it's just physically big and has at least a couple of major rides that you could do twice and still be very entertained. The other two WDW parks are a one and done, thank you ma'am.
The food in the actual parks is not as good as the park food at Disneyland or DCA. That said, Disney Springs and a couple of the Deluxe hotels have some very good restaurants to offer. These are big cheesy, corporate offerings. But you are on vacation and you probably just want a big, cheesy corporate dinner served up by a smiling waitress from Georgia. So just go with it, and enjoy what passes for gastronomy in the swamps of central Florida!
Eh, it seems that Covid has rewritten these rules. I think you are going to be okay without park hoppers, especially with the almost complete lack of nighttime entertainment in the parks.
Pre-Covid, people raved about Disney's Magical Express and its checked baggage system. During Covid? Who knows? It would seem to be a toss-up over doing the Magical Express thing, or just being an adult and grabbing your own damn bag off the baggage carousel and summoning an Uber in 90 seconds to take you directly to Coronado Springs to check in like a grown man. But maybe with a wife and small kids the Magical Express thing makes it easier? Either way, it's not going to be too painful.
Realize that the Universal Studios park in Orlando is just a big fake poseur of a theme park in a swamp. They haven't even filmed a Dr. Pepper commercial there recently, much less an actual movie or 100 years of movie history like the Hollywood original version of this knock-off theme park. There is no tram tour. There is no industry. It's a fake theme park built on a swamp. I would instead focus on the Islands of Adventure theme park next door, that doesn't try to be anything but a cheesy theme park in a swamp. Embrace it! Live it! Enjoy it! Don't try and lie!
If you want a real Universal Studios, you know where to get it in North Hollywood. When in Orlando just try and do what the swamp creatures do and spend a day at Islands of Adventure. Leave the real movie industry parks to California, when you get home.
Uber? I'm sure there's some shuttle bus or something that's cheaper. But just walking out the front door of your hotel and summoning an Uber to take you to the front entrance of Universal Studios has to be the best bang for your buck. You are on vacation, don't try and save 5 bucks by making your life more difficult than it needs to be.
No! I love this! Mainly because I don't have to do it and can live vicariously through you. But you are young, you are healthy, you have disposable income. Do this! Don't think too much about it. Just do it! And take lots of pictures! Especially take pictures with people wearing masks and obeying Social Distancing, because 20 years from now your kids are going to laugh hysterically at it!