AK closes at 7:00. If I were to get into FoP standby line at 6:00, is it feasible to think I can make it from AK to MK in time for fireworks at 8:00? Or should I plan to hop to a different park after AK, to enjoy a 9:00 close, and try to do MK fireworks a different day?
Using only Disney transportation.
I’m gonna say no. The line could still be an hour at that point. Depends on the time of year!
Also gonna say no. Bus transportation out of AK can be real spotty. If you miss a bus, you could be waiting a full 30 minutes before another one pops up. You might be able to grab a Contemporary or GF/Poly bus if you miss the MK Hopper one, but it’ll be more luck than anything and tough to plan with a tight timetable. Oh and the MK bus will also be fairly swamped because you’re definitely not going to be the only one to have this idea. 
Then once you get to MK, hoping to get any sort of acceptable view for Enchantment after 7PM is going to be a feat. MAYBE you can snag a spot over in the “overrun area” (east of the plaza restaurant), but that’s still kinda a garbage view (though better than the train station area currently).
If you’re going to transition, I’d try for Epcot. Harmonious will yield a better experience I think.
Thank you. That’s helpful. I have three nights and trying to do both nighttime shows. My original thought was to keep EP and HS on the same days since they’re so easy to get between and then just deal with the hardship of getting from AK to MK,
But with staying off-site and no ILL (thus no early entry and no FP line), it’ll be best to ride FoP as close to park close as possible. So that’s a little limiting. Hopping to EP sounds like a good plan. More travel options- I assume I’d try to take a YC/BC/BW bus?
Is there a particular park, between EP and HS, that would be better to travel to MK from?
Yup. But I think they’re all the same bus(I could be wrong now that I’m thinking about it). But still, the benefit here is the cushion of time. You can even grab the Contemporary bus and then monorail over and STILL have enough time to catch Harmonious.
I’d say EP. Monorail over then Ferry or Express Monorail to MK.
Is this because you don’t want to pay for ILL, or because you assume none will be left by the time you can book? If the latter, there are drops through the day.
Don’t want to pay for ILL. We’ve got a house addition starting in March and the only reason I’m getting away with doing PH tickets is because I worked that cost into our initial budget without discussing the option with DH. But he’s pretty against paying extra for G+ and ILL at this point, and I’m not doing anything to change his mind about it. I’m not really sold on it. We both agree the only “must do” for us is FoP.
I think you are half right. YC and BC share a bus, but BW has its own.
It may be that way sometimes. When we atayed at the Swan first week of Dec 2020., YCs busses did not go to BC. We used them 2 days, at Magic Kingdom and Animal Kingdom. (Tried BW bus stop to MK and hated it.)
When I was at CR in Dec we shared a bus w WL. Wtf?!
Yup that happens sometimes since it’s so close. Same reason poly and gf often share buses.
It’s a wonderful excuse to depart at WL and then get on a boat! 
I’ve been on a bus where it shared bc and bw. I always thought YC and BC used the same buses
Well darn I didn’t think of that! Too bad it was on my 36 hour trip and I had no time for disney transportation cost cutting BS