Since the speedsters on the CW series The Flash and in Batman vs. Superman are both named Barry Allen, what does their existence point to?
Multiverses already exist in the CW series and with the cameo of Flash in Batman vs. Superman, it is growing a little bit confusing...
Will both the iterations build up to the DCEU or will the CW version be dropped in the near future?
From a production standpoint, the movie and multiple television universes are entirely separate. You can see a graphical depiction of the current DC/WB landscape in this objectively excellent blog post on our amazing blog.
The man in charge of the DCEU, Zack Snyder, has repeatedly insisted that the TV universes will be separate from the movie ones:
The director went on to add, "...I think that's sort of the thing I've embraced, and as opposed to trying to shoehorn all of these storylines into a single universe, we let the characters exist in multi-universe, and therefore it's a lot more fun and a lot more value for the audience. They get to see their favourite and most beloved characters on different adventures at the same time in different universes and it really makes the meal a lot richer and a lot more fun. We get to go with these guys in all different directions and that's really the joy of what we're trying to do over here at DC." src
The fact that the Arrowverse already has a multiverse of it's own isn't going to impact the movie universe. If you want, I supposed you could consider the DCEU just one of the numerous universes in the multiverse, but it's one that the CW Flash will never1 visitar.
So far, this has resulted in a handful of characters that exist in more than one universe, played by different people with entirely different backgrounds:
"Even if Grant Gustin is my favorite guy in the world and he’s very good, we made a commitment to the multi-verse [idea], so it’s just not a thing that’s possible." src
The Suicide Squad has appeared multiple times on seta, including Deadshot and Amanda Waller. Both of those characters were killed off prior to the esquadrão suicida movie, where they've all been recast. (There was also a very brief Harley Quinn Easter Egg-style cameo, but the TV guys were quickly told she was off limits as well.)
Katana -- who was Masao's wife and Oliver Queen's friend on seta, is going to be a part of the Suicide Squad in the upcoming movie.
1Until DC/WB changes their mind.
He was explaining why Ezra Miller was cast as the Flash for Batman v Superman over Gustin. From o NY Daily News:
“Even if Grant Gustin is my favorite guy in the world and he’s very good, we made a commitment to the multi-verse [idea], so it’s just not a thing that’s possible.”