No cabins on deck 4/5 on Freedom, so it is 3 for a window or 6 for a balcony. Mid hump is a good location.
Low down and near as possible to Midships will give you less movement as to with window or balcony is up to you we like a balcony, but both will have the same facility's and same square footage.
Given the size of your ship your will be going on and it will be fitted with the latest propulsion units plus the more sophisticated stabilisers low down or high up shoiuld have little effect but midships will ceratinly do no harm. If you are going to the Caribbean it is often like a mill pond unless you are going during the hurricane season July/October when it can get a bit choppy, but unlike an island the ship can change course if necessary. On one cruise we headed further into the Caribbean and yes we missed a port but we missed the worst of the rain and choppy seas.
Totally agree with Buckley... if you find a cabin near the middle on decks 4/5, you should be absolutely fine!