All that said, in your shoes- I'd consider the new Animation resort over two rooms at POR. The new Animation resort does not have a pool slide, but it is brand new. The food court looks really excellent. The buses there will be good, thought he resort is going to be quite popular.
Another thing to consider is thatthe offsite house probably costs less. I'm not sure. You will save money on food if you opt to eat in your room/offsite restaurants. Many of the offsite choices in Orlando are chains- evey chain under the sun - but there are many fun choices if you live in an area that doesn't have many restautrants. And even if you stay offsite, you can always eat onsite.
To answer what might be your other question - why do I stay offsite - I pick offsite for several reasons. One is variety. Many offsite resorts are very nice. Most of our offsite time is when we plan to visit non-Disney stuff. Orlando has much ot offer besides WDW (though if you've never been, Disney is big enough and complicated enough that you should stick with just WDW)
We usually get a car, so sometimes we stay one night offsite to save a few $$. If I have a VERY early flight home- we sometimes opt to stay at the airport Hyatt the last night. It's less $$ than some Disney places, very nice. you roll out of bed and you are AT the airport. Easy.
What every you choose- I will say this - get everyone on the same page!!!!!! It is SO mcuh easier to have everyone stay ni ONE place witha big group. Also come up with a basic plan each day - which park and one sit down meal.
Witha big group - if you stay onsite - consider he dinign plan. It won't save much money - but all meals will be prepaid. (I like the
DDP with on QS meal and one TS meal). For us that is WAY easier with a big group.