How fun! I did 4P1D last July with my 11 and 9 year old DDs and we had a blast! Here my planning thread and relevant part of my trip report in case it helps.
We also started in AK and think that’s a great way to go - it’s nice and cool in the mornings and just feels beautiful and relaxing. And if you’re not planning on rope dropping FoP then you can just stroll in calmly a few minutes into early entry once the crowds have headed over there.
We also decided to make LLMPs for our second park (HS) rather than for AK, which worked well. I think your order of parks should depend a bit on your must dos - and your confidence in grabbing LLs at drops. Finishing with HS (and Fantasmic, which we love!) sounds lovely. We finished with MK because it was open until 11pm.
Agree with @Sunshiney_Disney_Momma that you might struggle to get LLMPs for Remy and TT later in the day, though they do both have single rider lanes which work well (and since it’s a 3+3 seating arrangement you sometimes ride in the same vehicle behind each other). You’ll also need to get lucky with drops or cancellations at HS. We had no problem picking up hard-to-get LLs later in the day because I used Genie. Highly recommended!
Have an amazing trip!