I feel like the combine will tell alot. I think he will only run in the mid 4.5s. He doesn't have great long speed. Im not sure about his short area quickness either, he flashes quickness in and out of his breaks in space when he is allowed a free release, but he often struggles to separate against press man. He does have great size and catch radius though. He is a tricky evaluation, he has so much production, but alot of it is against unranked teams. I can see why he could fall out of the first, in a deep WR class.
This is hard one. There are so many great players in this class... I will also assume you don't want us to include positional value in this.
The fifth one is extremely hard for me. I can argue for like... 5-6 players here... Derrick Brown, Lamb, Jeudy, Andrew Thomas, Jedric Wills... hell... even Tristan Wirfs needs to be in this discussion, even though he will probably be RT, he will be a great one IMO. I think I will go with Jerry Jeudy here as my last one.