If it were us we would absolutely do a 2 BR, just so kids have their own space and us ours. There are 5 in our family and were doing a 3 BR, having our own personal space on a vacation is a huge sanity saver.
Secondly I would look into Disney YES programs and put one of your kids in one while your there and then purchase the 7 day tickets through them, heck or even 10 days for a few $ more. The programs only take 3 hours (usually end by 11 am), are an amazing experience, and save you almost 1/2 the cost on your tickets. We got 5 7 day hoppers w/ water parks and quest for just over 1k where it would have cost us almost 1900 (saved $888). For the 3 hours time (and experience) its SO worth looking into if there is one running while your there.
http://www.disneyyouth.com/individual-enrollment/
Then use the money saved and consider the other parks.