Honestly... I', beginning to look towards asking for council permission. Look at it like this:
People know we are coming here to ask them about it. The most suspicious course of action would be NOT DOING IT. I don't see how we'd have any more trouble after asking than before - I very much doubt they're going to put us under guard for expressing interest, considering the support we've had, and we're doubtless going to gain valuable knowledge from it. And there's always a chance they might have a damn good reason to send us out - if there's really a potential of the elves getting involved in the wider world again, they might need someone to go out and do some scouting of some sort.
And if our father is leading the armed group escorting them out the vale, well - in that case, I have several additional plans that might work pretty well even if the council turns us down.
The biggest issue here will be convincing Omo - and honestly, if he wants to go on his own, I say we try to organize some sort of meetup with him and try our own plan first even if he won't stand for it. I am 100% confident we'll still be able to get out even after asking permission - after all, if we threaten to kill ourselves if the border patrols stop us, would they really, honestly try? Wouldn't the whole point of stopping us be for our own protection? And once we're outside the forest, it's not like they're going to follow us...
At this point, I say we return to Omo and start discussing potential ways to do this, and, again, ask why leaving NOW is in any way superior to waiting a couple days.