As far as I'm aware, unprotected drafted players and their contracts become the property of the expansion team. If Zetterberg we drafted and were to retire, that cap penalty would have no effect on us as the contract was moved when he was drafted.
I'm aware it's unlikely Z and Kronner don't get protected, I just hope loyalty doesn't cost us a solid prospect
While CBA doesn't specify this exactly, every time transfer via expansion draft is mentioned, it is treated exactly as in any other case. So cap recapture would still apply to Red Wings since they took advantage of paying more money than AAV to Z (or Kronner). That means if he retires before his contract ends, DRW will face cap penalty equal to net benefit divided by number of years left on his deal. Total recapture pool at the end of 16-17 will be 12m$ for Zetterberg and 4m$ for Kronwall. So that would be even more harsh than I said: 4m$ cap recapture penalty after retirement 3 years early, 6m$ for 2 years, 12m$ for the last year.