Why not Hardwick?
Just my opinion but I think he is going to be a career assistant - very much the Harvey's about him.
Hardwick has been involved in too many premierships/success as both a player and in coaching to be a career assistant. Harvey may have been an assistant coach for Essendon's 2000 Premiership, but he'd only been out of the game for 2 years and hadn't ever left the club. Since 2001 he's had pretty mediocre results at both teams he's been involved with.
Hardwick left the game in 2004 winning a 2nd flag with Port, went straight to Hawthorn as an assistant coach in 2005 and won another flag as an assistant coach last year. Can't see the similarities, sorry. Not saying he's a guaranteed success, but he ticks all the boxes.