just wondering, will any of them appear in future justice league movies? I assume DC want to follow the Marvel model with all those avenger movies and stand alones
Unlike marvel that connects all their television and movie properties, Warner Bros/DC comics have a mess. 
Tv world and movie worlds are separate.   You'll see a different flash and different arrow in the movies, unfortunately. 
Arrow and Flash Tv shows are connected. 
"Gotham", which I hear is kinda weak, is completely separate from everything. 
It's my understanding that super girl will be separate from everything as well, but maybe it's connected to arrow and flash.
I gotta say I watched the first couple seasons of "Arrow" and kind of enjoyed it.  It's not great. It has obvious flaws and got a bit boring.  The female lead almost ruins the show for me... She all kinds of awful.  It rips off batman begins in many ways, but it's a nice guilty pleasure show. 
I just finished watching the first season of "Flash" and gotta say I enjoyed it more than "Arrow". I liked the characters more.  It's nerdier.  It might be the most comic-book show I've ever watched.  It has tons of obscure characters, time travel, alt dimensions... I dig it.  Again, not a great show, but for what it is, I've found it consistently entertaining so far.   I was never a big fan of the Flash character, but I have to wonder how hardcore comic fans feel about it.  Seems every week they have another character on there... My guess is fans of the character love it. 
I loved superman as a kid. I have almost no interest in super girl.  I'm familiar with the actress for Internet reasons, but beyond that... It will need amazing reviews to peak my interest.