Is it possible for retired players to become head/assistant coach candidate?

in association mode or my career? In my game there have been several players retired, and I wonder if they will ever show up in the head coach or assistant coach list should I decide to fire my current head coach or assistant coach. Anyone found if this is possible or not? And is it okay if I edit the head coach list in RedMC to make a retired player into head coach/assistant coach?

As far as I know, the players can never be coaches after they retire.

Oh this is kinda pity, is it possible to make them into coach by editing the coach list in Red_MC?

Yes you can make coach now - for a team in this season or as a coach waiting to have a contract. However, you need to buy the feature which can edit the staffs in RED MC.