I wouldn't lock into a PF for that pick but take the BPA.
C's are thinnest in these areas:
Center
PF
SG
PG
SF.
Danny should be looking at the best Center, PF and SG prospect available at the time he picks. None of the prospects mentioned are going to make much of a contribution if picked.
Consider this, Doc has been unable to integrate NBA vets into his defensive schemes for the past 4 years at midseason. He's never incorporated rookies into his rotations unless forced to do so due to injuries to veteran players. Considering this is a weak draft where the majority of these options would be second rounders at best, does anyone really think they'll be good enough to see the court while Doc is coaching this year? (We may think a player's good enough, but Doc won't).
The pick this year is an investment for next year. plain and simple. Not knowing how Danny will handle all the contracts coming off the books after next year leaves me unsure if the best move is to take a risk on someone with potential (such as Tyler) or more of a sure thing to be a bench role player (Johnson). If he's recycling the big 3 again, probably go with Johnson. If he's retooling, probably go with Tyler (or Marshon Brooks as Ray's replacement at SG if he's still there).