Lots to answer. Garrett would top the Cards' board. Normally you keep people on your board even if you think they'll be gone when you pick. They could drop due to some stupid rumor and you'd have to decide whether to take him or not; see Nkemdiche.
I debated Howard at 20. There's quite a few good TEs in this draft, though Howard is the best. Baker would be round 1. Others like him more than me. Cunningham seems to be dropping inversely to Reddick's rise.
I warned you CBs are all over the place. Lattimore is very raw and will get beat often if you put him at the number 2 corner now. It's true he has the skills to be great, but I see too many CBs get their confidence destroyed by getting beat too much. Keep in mind his performance was helped by Conley taking the toughest receiver. Lattimore has tons of flaws but is so athletic everyone seems to assume he can overcome them. His hip aren't smooth, I sometimes see a hitch. He doesn't sense when to turn his head. They burn you in the Pros for that. He tends to grab speed receivers. He hesitates to chase when beat. Finally he seems to have tight hamstrings.
I'm not sure any rookie CB is plug & play. Humphrey is tough-minded, talented, but also needs to learn much. He's outstanding in run support. He's a true outside corner working better in space. Shows sophistication in route recognition. He's very durable and you know I love legacy players.