Not that I know much about these QBs, but can you give us examples of why they're sure-fire 1st rounders? Anything will suffice. I'm not trying to be a dick, I'm genuinely curious.
IMO
Pickett doesn't have elite arm talent, but that doesn't mean he has a weak arm. He has plenty of arm strength to make all the NFL throws with velocity. He knows how to read defenses and goes through his progressions quickly, and throws with great accuracy, timing, and anticipation in rhythm. He's also mobile, not a scrambler per SE as he can do that if needed, but can escape the pocket and keep the play alive looking down field while throwing accurate on the move. Shows himself to be a leader his teammates follow. The biggest gripes against him are his fumbles, which most were due to how he holds the football when moving around in the pocket to escape pressure, and I believe is correctable. He also on occasions leaves clean pockets when all he has to do is shift his position in the pocket to reset and make the throw, again I believe this is coachable. I do not worry about his hand size really due to his double jointed thumb that makes his hand measurement weird, but when measured holding the ball it's over 9 1/4.
Willis has elite arm talent, and escapability, combined with a difficulty to to tackle. Hard to guage pocket presence and pocket accuracy due to him playing with accountants, and running for his life on most drop backs, but he has shown accuracy, and when given time has shown the ability to cycle through progressions. This was few and far between, as he rarely had time and was trying to "carry the team" on his shoulders to make a play rather than what was given to him. Much of his accuracy issues come from mechanics, and much of that I believe is coachable. But I don't expect him to become a pocket passer fully in his career, and he somewhat reminds me of McNair in that he's thick and elusive even though he's only 6'0, but can make throws from the pocket and on the run. He's absolutely the biggest project, has the biggest potential to be a Mahomes or Allen, but also the potential to be an RG3 or cam newton or worse (guys whose legs stopped being helpful, and never got the passer part down completely to make up for the loss of reliance on legs, whether injury or NFL scheming them properly). He shows excellent character, a likeable personality, and guy that his teammates will love. He has intangibles that can't be taught, but it's all reliant on if he can fix his mechanics and his "I have to make a play myself always" play style.
Ridder has a strong arm, not elite, he showed the same type of throw at his pro day as Willis. He is a consummate and mature leader. Ridder desires to be the best to which his attitude will endear him to his teammates, and they will follow his lead. He shows the arm to make all the NFL throws with velocity, and he shows mostly consistent accuracy when throwing with time and anticipation in rhythm. He also has great mobility as he can scramble when necessary and escape pressure to make throws down field. His tape shows him going through progressions except on the rare/random occasion when he stares down a receiver, and he understands defensive schemes and how to attack them. Where he has problems is his footwork and mechanics as he doesn't always throw from a wide base, and clicks his heels on occasions or even throws flat footed which cause his sometimes baffling inaccuracy. He also uses touch too many times on throws when he needs to just rifle it. Things I also believe are coachable. He is a high character, and I believe is the type of player you would want leading your team.
I like Corral and Howell, but I believe they are just on the fringe, but would make sense for them to go late first (maybe I'll break them down as well at some point but this has already gone on so long)