It is one of my dreams and I wouldn't say it's impossible at least but I know a few people aiming at that goal and already published manga like series.

I think there already are foreigner mangakas or light novel authors. If you want to become a mangaka in a more traditional sense then it's difficult. You need to find an already established publishing house in Japan and they get hundreds of samples everyday so it's not easy to get selected. Even if you do get selected you must maintain a high reader score for your manga to continue. And you must only write in Japanese.
But today you can also publish your work on internet in any language and gain recognition for it. They are called webtoons i think.

there are already many for foreigner mangakas in industries now a days..im sure it will be even more in future infact there might be even a competition among them.....he he e

its probably hard but right now the author of the animanga series RADIANT is FRENCH so its possible

Unfortunately not, I don't think foreigners would be able make a proper manga series, as it's something that's characterized as being japanese.