Hello,
Can unit with Steady or Relentless make an free attack after doing embark move action but before being taken off the field?
In RRG for Embark it says " To embark, a unit performs a standard move that puts its unit leader into base contact with a friendly vehicle that can transport that type of unit. Ten, the unit is removed from the battlefeld "
and also two points are specified:
• Any abilities that trigger afer a unit performs a move trigger
afer a unit embarks or disembarks, if able.
• Any abilities that trigger afer a unit performs a move action
trigger afer a unit performs a move action to embark or
disembark, if able.

E.g. snowtroopers will perform a move action to embark, so imho second bullet above.

If unit first embarks it cannot shoot, but what comes first: free attack or embarking? And why, i.e. based on which rule?
Thanks!

EDIT: Ok, i understand now that removing models part of the text, is in fact part of this special move action, thus when Steady would trigger, minis are already inside and cannot shoot.

As you state in your edit, the move action isn't completed until the unit is removed, at which point Relentless/Steady is unable to trigger.