I assume I can use my dining credits from the POFQ reservation all day on Thursday, and then start on the AKL dining credits on Friday.
Yes, you can still use your POFQ dining credits until 11:59PM Thursday night. Finish using those before you start to use the AKL credits. However, those will be available to you as soon as you check into the AKL on Thursday.
One last question on this for now is: this leaves an issue since for one reservation we purchased 8 day parkhopper ticket, and for the next we purchased 3 day parkhopper ticket. So if one key gets me in for 7 days, yet has 8 days on it, do I use this set to get into the park on the first day of our second reservation. I know this confusing, and maybe not an issue for this board, but I thought I'd ask while (at least) i'm on the topic.
I have another suggestion for this. For paid dining you need to purchase at least a 1 day ticket for each person which you've done or a 2 day ticket if you have free dining (I'm not sure which you have). However, to save some money you could buy 10 day parkhopper tickets with the POFQ reservation since you'll be there for 10 days (arrive Friday, leave Sunday). If the tickets are on the KTTW card, you'll just continue to use them throughout your entire vacation. Then, with the AKL reservation, I would purchase the MINIMUM ticket required (either 1 or 2 days depending of paid or free dining). DON'T accidentally use this ticket at the turnstiles, but instead save it for a future trip. As long as you don't use it, it won't expire even if it's on the KTTW card. I know this adds a new wrinkle to your ticket plan so feel free to ask more questions...maybe on the Theme Parks Planning and Strategies Board.