I would say a week is not enough. If you just do Disney. That's 4 themes, 2 water parks. Disney springs.... plus you may need rest days or want to visit the outlet malls.
Minimum would be 10 days
Everything is changing at Disney at the mo and you don't get the perks like you used for staying on site. Yes you can get early entry but it's now only half an hour.
There is transportation around Disney but they no longer do magical express from the airport so transfers have to be thought about.
No more free fast passes that need to be booked 90days in advance. You can only book on the day and you have to pay for them!
We are looking at going the same time next year. If you look at the weather other there now it's fine. Some clouds maybe but temps in the high 20s. Rainy season is in the summer.
If you book everything separately you have to be aware that your booking won't be AToL or ABTA protected. But yes it is cheaper to book things separately. We usually look at flights on sky scanner but they aren't currently showing direct flights for next October yet.
Personally we Always stay in a villa. Eating out all the time soon adds up and I'd rather have the cash to spend on other things. Plus I wouldn't want to be restricted to just a hotel room. The parks are tiring and it's nice to be able to go back to a villa, sit around the private pool and chill out in the afternoons.
Florida Tix are very good for booking park tickets but look at other sites too to compare prices.
Car hire is looking really expensive ag the moment but using Ubers etc is a popular thing to do as it saves on the parking fees ($25 a day) but if travelling with kids that need car seats could make using Uber a difficult.
Also if you stay on Disney site and hire a car you still have to pay to park on site.
It's a great holiday and I love going but it can take a lot of effort and organising to make the most of it. But it's so worth it!
Look at the DIbb website and there are Facebook groups that are filled with knowledgeable people about planning a Disney trip.