This is something every Marvel and Disney fan can enjoy, and for lack of a more eloquent thing to say... so epic...
I find that so many people, if they were to do a Marvel/Disney crossover, instantly put Merida as Hawkeye. While I have no problem with that at all, this is actually cooler. Mulan is and continues to be one of my favorite princess. Unlike her Disney sisters of yesteryear, she fights and believes in herself. Originally she doesn't fit in as the normal mold of women in her society, never much one for arranged marriage or being sub-servant. She, to me, was the original Merida. Both their stories are similar in the sense that it's about stepping outside of yourself and what you're expected to be
Your anatomy looks great, and all proportionally sound. The arms look a little too skinny for me, but that's my only real woe. The expression is kind of haunting and intimidating, not at all Disney. However, I still love it. In reality, Mulan isn't so much of a princess as a warrior, and that to me is the face of a warrior. As for her attire, I appreciate that you stuck true to the Disney design, but I think I would've liked some sort of nod to Hawkeye's really cool super suit. The picture, while I see the Marvel in it, could also just be interpreted as Mulan holding a bow and arrow.
Overall, I really enjoy this work, and now I'm off to see the rest of your series. This work is fantastic and I'm glad to find an artist as great as you are.