Moritat and other IC joining squads

Hi Brothers,

Can IC's that dont have Bitter Duty join a unit, and then a moritat join the unit last? Excluding Apothecaries and techs obviously.

So can a Praetor or Centurion join a unit, then the moritat, then that's your lot?

If they can't, can a non Bitter duty IC still ride along in a transport with a squad that includes a moritat, or vice versa, can the moritat come along for a ride with another squad, assuming there is room?

I'm after taking a squad with my warlord in a spartan, and would love those Rad grenades to help out on the charge