That reminds me... Is the Flynn we know actually from that future time? And what prevents the lifeboat from going forward as well as backward in time? The claim that you can't coexist with yourself from another time is clearly erroneous.
I do believe this Flyn is a normal Flynn i.e. not from the future, and from this original timeline, well you know what I mean.
Thing is that about a couple of episodes ago, I remember him telling Lucy, something like:
"Some years ago, I was at a bar, sad because of the loss of my family, and then you came up to me, You (Lucy) but you looked like 5 years older".
So I understand that some years ago, Flynn met the Lucy from the future, and that's when Lucy somehow "recruited" Flynn in this adventure.
I'm not sure if the show has addressed the possibility of the lifeboat travelling to the future and therefore I understand it is possible.
And so in this show, there is absolutely no problem with coexisting in the future or past.
I also believe that claim of non-possible coexistng with yourself is in error as it applies to this show.
And at a personal level, I am believer in the possibility of traversing time and time manipulation and that there is nothing against the possibility of coexisiting with yourself in another time.