Welcome to the wonderful world of Disney planning! haha. I love putting together trips, and Im glad your wife knows you do as well!
Genie+ is very convoluted and confusing. I highly recommend watching some videos on YouTube (AllEars and Disney Food Blog have good visual tutorials) so you can learn the process and the rules. And then you MUST practice playing around with the Tip Board in the app prior to your trip so you can get the mechanics down.
I found that Magic Kingdom gets the best use out of purchasing Genie+ because there are simply SO many attractions (and lines are longer than they've ever been), so you will be able to get a lot done by correctly utilizing the app. Hollywood Studios feels like its necessary to purchase Genie+ if you want to experience everything, but you won't get as many lightning lanes out of it as in MK (but even if you only get 3 or 4 attractions from Genie+, you will save HOURS of precious time). You could do EPCOT w/o Genie+, but I found it very useful for blowing through all the future world attractions in quick succession (plus eliminating a wait for Ratatouille) and thus having more time to wander and explore World Showcase. Animal Kingdom I really don't think Genie+ is necessary, but its up to you and what experience you want. Again, watch some videos on how to use the system and see what strategy works best for you.
My must dos/tips:
*Make sure to spend some time OUTSIDE of the parks! This is one of the best parts of an adults only trip. There is simply SO much to do at Disney. And some of the best dining and bars are actually at the resorts.
*If you want a romantic, fancy dinner with your wife, I recommend trying to grab a dinner reservation at
California Grill at the Contemporary around fireworks time. Hard reservation to get (though easier with a party of 2) but oh so worth it. Other top fancy dining recommendations are
Flying Fish at the Boardwalk (the seafood is to die for, but surprisingly they also have my favorite NY Strip of all time! And the pork belly appetizer is mouth watering) and
Jiko at Animal Kingdom Lodge.
*Take a midday break. If you are trying to do a park from sunup to sundown, you will need a respite! Keep travel times in mind if you want to go back to your resort for a nap or to freshen up (it may mean hours out of the day). But its easy to take a quick break without going all the way to Port Orleans. For instance: during a Magic Kingdom day, hop on the monorail and head to the Contemporary for a delicious and affordable lunch at
Steakhouse 71. If you aren't looking for a long sit-down meal on your break, head to the Polynesian instead for a quick service meal at
Capt Cooks. Cheap but yummy food, and you will be able to eat without the hectic energy of the park! (plus there's dole whip and a great bar and the property is fun to explore). Other parks are harder to leave to go to somewhere close by, but you could at least schedule a lunch at a sit-down meal in the park (this gets you sitting in AC when the crowds and heat are at their peak).
*Schedule your park day the right way! I like to take advantage of the early morning entry to knock out a headliner or two. I then continue to do as many headliners as I can before lunch time/midday. During this midday period, I'm eating inside, and taking time to do indoor shows (low/no waits, plus the AC). The heat will probably not be as brutal for you in February (I'm usually there in early summer) but wait times will still be at their longest midday.
*Make sure you take in the "little" experiences and classic Disney rides. Bigger thrill rides and new stuff like Guardians of the Galaxy or Rise of the Resistance are amazing. But make sure to take in classics like the Tiki Room (Walt's first animatronics), the Carousel of Progress, the PeopleMover, Spaceship Earth, etc. These, imo, are part of what makes Disney World so unique. It's easy to get lost in rushing from one e-ticket ride to the next, but sometimes you have to stop to take in the rich detailing of Animal Kingdom, or a street performer in EPCOT. Small moments are often what make the trip!