I think there's too much going on. You can do a steampunk Sherlock Holmes story. You can do steampunk and magic, (I love Arcanum.) You could do a magic Sherlock, but I would be skeptical and ask if you even read the original stories. I don't know if you can do a fish-out-of-water steampunk magic Sherlock Holmes mystery with a love triangle. I'm exhausted just typing it.