Yes and no... it's pretty clear that the Valar should not have summonsed the Elves to Valinor, but once there, it wasn't that they were forbidden to leave. They just sort of left in a hurry, without asking permission.It is true they weren't forbidden to leave. But then they dramatically screwed up the process of leaving. They attacked and slaughtered the Vanyar, their own kin, to get their ships.
The ones under Fingolfin, marching north along the shore, were confronted by Mandos who ordered them to return to Valinor to face judgment for their crimes or to be cursed as rebels. A few returned, but most continued onward. These were the ones who had to gain forgiveness before they were allowed to return to Valinor.
Mmm... they killed the Teleri, not the Vanyar, for the ships. And that was on the part of Feanor and his folk, not the people of Fingolfin. (There were fewer of these and they were at the back of the march, I think they actually stopped to pack). You're right, that the Doom of Mandos prevented them from returning until it was later lifted. By the time of LotR, the Ban was long gone, except for Galadriel, and that was because she herself had refused to accept the Ban being lifted from her. That sounds confusing but I think you understand what I mean.
I lost the thread of this conversation. Is there a point we're supposed to be making or is it just Fun Elf History Trivia night at the Green Dragon?