We would stay on site.
With that many people on site all the way. It makes it so much easier for everyone. If someone wants to sleep in, or stay out later. If someone forgets something its easy to get back to the resort, if your mom and dad want to take a break its easy for them to get back to the resort on their own on the bus... I would not want my mom or dad trying to navigate around Orlando, with all the tourist, and all the construction its very easy to get turned around, and the local traffic... its crazy town....
While I think POP is cute, I would check out maybe moving to a moderate, for some more space so that you can move around more easily, and you know your other family members will be in and out and in and out of each others room. Plus the pools have slides, and hot tubs and some neat little kid areas.
When staying at a Value Resort you get the QSDP, again you might want to think about upgrading to the regular
DDP so that TS meals are available to you. Character meals are a must when you have a group this large, the pictures alone would be priceless...just think pictures of your mom and dad with Mickey and Minnie, Winnie the Pooh and gang or Princess...
I would run all the numbers, backwards and forwards to see what's the best option for your group...
We have done big groups like this... We had talked about everyone doing their own thing but when it came down to it... We really spent most of our time together, especially at meal times and sitting down at a TS for a meal was great...honestly those moments and memories are what we still all talk about today...or when whoever put on the sombreros in Mexico, or the Viking horns in Norway... When we ate Mickey bars and watched the fireworks over the castle... These moments are what its all about.
I also have another idea... As a family you might want to talk about giving Disney GC for presents this year, starting with Christmas... Starbuck or Landry's gift cards to spend in the parks... We did this when my DD got married and they honeymoon at WDW... We started giving them Disney GCs when we had a small engagement party then the whole family got in on it... all in all they had around 600.00 in gift cards of extra money for their Honeymoon...