hi, I´m using light-return strategy. So when my majestic Mech Okha comes to the field from the removed zone by the effect of the return of the different dimention, then what will happen to him?

Will IT GO TO THE GRAVEYARD, bacause originally IT died and went to the graveyard with NO tributes, ramoved and then special summoned into my side of the field? ALL IN THE SAME TURN

or...

does he has to leave after my turn ends because of the effect of Return from DD? Same thing can be asked for Majestic Goryuu

It having been destroyed before has nothing to do with the effect of these monsters. So it will return to the RFG area at the end of the turn.

It only "remembers" itself being NORMAL Summoned without Tributes if that is what you actually did at that time...if SPECIAL Summoned, it does NOT send itself to the Graveyard...

In this case...it gets re-removed by the effect of Return from the Different Dimension...