I would say EP is unnecessary, especially considering the amount of time you'll be staying at the resort. February is part of the slower season, no major holidays that typically bring crowds, and the dates are nowhere near spring break. The only time during the whole week I can see a difference in days is the weekend / Valentine's day (since it's on a Friday), but other than a usual slight difference since people have Sat/Sun off (due to work/school) and Valentine's would be date night, nothing that screams you'll need an EP.
If anything, if there is a day in which it is bizarrely busy and the wait times seem high to you, you can always get an EP for that day. I don't know if that is within the budget, but it's just something you're aware of that you do not have to purchase the EPs for all five days. However, once again, I do not think it will be necessary, especially if you take advantage of EE.