I think the real worst case scenario involves us trading back and then missing out on our targeted guys... We are in a prime position to get a potential pro bowler and shouldn't get too cute.
Assuming we stay at #5 - the only truly awful scenario in my mind would be drafting Baker Mayfield, an undersized project who will need time to adjust to reading NFL defenses and probably won't help the team in 2018-2019.
My preference is Nelson or Barkley - followed by the QBs and Chubb.