The draft will happen, it wasn't just invented and before media culture it was done just over phones without video, now they can use feeds etc and get it on the air, teams can still call players and do skype type interviews with prospects if they want. Other then their pro day work outs on Campus most the information is already tallied on players, its injury recovery prospects and late work outs for them teams will have to roll the dice on more.
The Season is a ways off yet, OTA'S will suffer, but again playbook study can still happen via electronic meetings of player groups and discussions if organized, they will have to do individual workouts more, what will be missed is players needing recovery and getting into NFL shape with the staff. They may have to have limited work outs as in head counts and or go by position groups leading up to the season.