What about booking through a UK
travel agent . I know this sounds mad as you'd think that direct would be easier, but I think they may be more helpful and might get you a better deal.
How about a suite in the Seq Lodge . They may get fastpasses and It's not that much more of a walk.
Your other option is to stay offsite. I can recommend the Marriot village and it will definitely sleep all your family.You could then buy dream annual passes which get some fastpasses (can someone help with the number
)Only downside with this is you will have to go on shuttle to the parks (which is quite infrequent)unless you hire a car. The dream pass entitles you to free parking. Dream passes also get you into the park an hour early.
Just my tuppence , but I hope it helps.