You talk a lot about listening practice, but how good is your reading? 7 months at one hour a day isn't much time, so you should already be able to understand and answer at least part of an
example N3 test (this is not the complete test, just the part that focuses on grammar - other parts can be found
here).
I'm not sure how much of an edge your knowledge of Chinese characters will give you. Firstly, characters that are commonly used in China may be used barely or not at all in Japan (and the ones that do reoccur are not necessarily used in the same way). Secondly, the N3 test still has lots of furigana
Out of curiosity, did you drop Mandarin or are you attempting to learn both languages at the same time?