Hi! I may be able to help you.
I received the embassy recommendation from my embassy despite having the lowest Japanese language score of everyone who took the test there. I also was the only Arts/Humanities proposal this year.
My research proposal is similar to yours in scope. I am studying exchange and exhibition of visual arts today between Japan and the US. Of course, this scope is broad - and my proposed project is much more honed down and focuses on the dissolution of a very specific, long-standing exhibition exchange between the US and Japan, has very specific questions looking to be answered, has multiple case studies, and an end product of developing a new exchange. Being SPECIFIC and having an END GOAL will make you stand out. You say communication, SNS, and media... pick something more specific and concrete. They won't pick you for the recommendation if you say that. The project would simply be too broad. In fact, someone in a past year's MEXT thread proposed a very broad "art and communication" research project and did not get recommended. Think of a specific form of communication. I would suggest researching something "novel" - or new (like a cutting edge form of communication for example), something specific to your region, etc. Be specific!
As far as language goes, take those Japanese classes! Study hard for the Japanese/English exams - you need exemplary marks on one of them to get to the interview stage. Someone who doesn't know the language but is taking steps to learn it will still look pretty good!
Now, I truly do not mean this to be rude, but I think this is important. It sounds like you are highly motivated to apply for this in order to live in Japan and don't necessarily have a research project fleshed out. The big factor in which research proposals get picked is "Why Japan"? Wanting to live there will not be seen as a good reason. Wanting to learn the language is not a good reason either. Your research project IS the reason - why should your academic research be done in Japan? Just have to convince them why they should pick and ultimately fund your academic research!