So far we have one child Barry in the house, one who removed child Barry, one who watched, one who warned the watcher not to intervene and one who stopped the Reverse Flash.
Isn't it getting a bit crowded in there? Especially since at some point in season 3 there will be one Barry to stop the one who stopped Thawne and who will then possibly become the one who warned himself earlier
I'm going to enumerate the Flashes that are in the room and their roles so that we can maybe make sense of this. Kevin Smith on his podcast said he couldn't wait until the final season where there are 87 Barry's in the room.
YB - Young Barry who is native to this point in time
S1B - Season 1 Barry who's hiding in the other room after travelling back from the S1E23 Finale
S2B - Season 2 Barry who stopped the Reverse Flash (RF) from killing his Mom in S2E23 Finale
S3B - Season 3 Barry who will have to go back at some point in S3 to fix the mess S2B made.
SXB - Season X Barry who chased the RF back in time. He has a bright red costume instead of a maroon one. He appears to be from the farthest in the future.
It is my understanding that SXB is the same one that tells S1B not to save his mom AND saved YB from the RF. S2B travelling back undid the timeline and that's why S1B faded from existence. I'm not exactly sure how you get a time remnant vs. getting erased from existence works. Why S1B didn't disintegrate like Wells-RF isn't clear. Maybe it depends on whether the timeline is changing as a result of your current actions? It's all a little Timey-Wimey.
I think we're in the middle of a self-correcting paradox and it will eventually stabilize when Barry stops going back in time to this point. I think SXB is the final trip from the farthest in the future. I suspect that S3B will go back and stop S2B (in the street, maybe), thereby restoring the timeline, unless there are future seasons who are still making plans to come back here.
There must have been an original Flash that started this all, but I'm not sure how to reconcile him with the SXB who tells Barry not to change the timeline, assuming they're the same person. Perhaps he learned from other experiences not to mess with events? RF-Wells said that he just moved up the timeline of how the Flash was created so it must have happened with the original Wells at a later date. This makes me think that we started the TV show in the middle of the Paradox and not with the "first" Flash. The First Flash must have had both parents growing up and still got powers later on as a result of the particle accelerator explosion.
I wish the writers were a little more consistent with how their time travel works. I get the impression that it's like magic to them, but even magic has rules; they're just very different. You still need to be consistent in order to play fair with the audience.