I can't speak to specific touring plans, but as someone whose DL trips have all been relatively short from the start (1-3 days), I strongly believe you'd be making the right choice to get park hoppers and purchase
Genie+. This will allow you maximum flexibility to take advantage of any short queues and other opportunities that pop up throughout the trip, especially if you're both comfortable with a lot of walking. It's so easy to park hop in DL.
I also suggest this tip: once you book a Lightning Lane for a specific ride, particularly popular ones that may not be available for several hours or until later in the day, go to Modify for that LL and then keep refreshing it to see if an earlier one pops up. I very often have luck getting much earlier times after booking the initial one.
For example, if it's 11:00am and I don't want to miss a LL for Midway Mania but it's not available until 3:00pm, I'll book it and then immediately (and regularly if it doesn't work the first time) modify and keep refreshing. It's very common to have one pop up for, say, 12:15pm, which you can just click to grab. I find it the most efficient way to maximize the number of rides I want to get done in only a day or two while minimizing overall wait times.
All that said, my absolute best recommendation (which it sounds like is not doable) would be to extend the trip to three park hopper days with Genie+. Even as a first timer, with a bit of research, you'd likely have no issues doing everything you both want to do in both parks - likely multiple times for many of them - plus Downtown Disney, and also even have time to check out the Disney hotels. BUT it could be done in two days if you do it right and have a little luck (I mean...Disney Magic).
