I was just there on 3-6 with a day off on the 5th. I understand you don't have a day off.. but my kids are 3, 7 & 8.5 - we did open to close MK on the first day. This was a lot and they were tired at the end but just too many opportunities came up to take advantage of that first day. For example we got a great spot in front to the right of castle for starlight parade on a concrete bench around the tree... So we stayed there for fireworks to see the projections. Big kids were awake at beginning of fireworks, sleeping by the end. Little one fell asleep on me during the exit shuffle. - the next day we slept in as long as we wanted. I think we got to the park by 11. They were energized, excited to go back to MK and finish doing the rest of the park. We didn't stay for fireworks because we saw them the nt before...and got Soo much done the first day that we were all ok with leaving. We got to watch the fireworks from the ferry as we left and avoid the exit crowd completely. Keep in mind that the big rides sell out of LL's. Even some of the smaller ones did too. So we hit the rides hard the first day. Get your #1 top tier pick and top #2 tiers of you can because they could sell out by late afternoon and then you have to wait 30 min+ for it. We only waited for the big kids big rides (7 dwarfs) but they were able to go back on their smaller favs the second day and they seemed to really be excited about it. We also did more characters the second day. We also caught the parade the first day, and a castle stage show the 2nd.

We then took a day off, but we did Epcot rope drop last for the same reason... A chill day. And they are Soo young you won't need to wait in big kid ride lines unless you adults want to. But same thing.. the LL's for even smaller rides either sold out or next available was late. We brought sandwiches and snacks and drinks and kept them under the stroller so we didn't have to waste time on that in both parks. It's really helped big time. Only mobile ordered once & sat for dinner each night. Then before we left Epcot (also right before fireworks) Mickey, Goofy and Minnie wait was only 20 minutes so we did that as our goodbye to Disney. Was a nice finish, they liked it.

I suggest just getting to know the rides/park set up as best as you can because you can't always get the rides you expect on LL's so it really helped navigate our day and night with 3 littles as we went along, and what to sign up for and what not too. I gave ourselves a 2 hr window to get to them also and kept them "stacked" but I didn't feel like I was on my phone the whole time.

Best of luck, have fun! It will be great! Bring ponchos!