From past experience, it's going to be very busy and very crowded. Not only MG and Valentine's, but it also leads right into President's Weekend and Daytona weekend. It's a time when folks are going to take some time off, get out of the cold/snow, and head to Orlando and Disney. But, as with other busy times at Disney, you can certainly navigate it by planning early, utilizing
Genie+/ILL (if you're looking to do the attractions), getting ADRs (although you've already missed the 60-day mark for that)....
Festival of the Arts will still be going on at EPCOT during that time - our favorite festival. We actually thought EPCOT was the most crowded of the parks when we went a similar weekend in the past. Hope you have a great time if you go!