I want to echo Russ's point. The market for humanities academics in areas such as gender studies and sociology is a competitive and arguably shrinking market. Obviously if it's something that you want to do then by all means go for it, however, I would consider what you would want to do if you don't manage to get one of those academic positions after completing your PhD. An arts degree can be useful, but often many of its graduates don't end up working in the field that they studied in solely due to limited positions in academia.
I feel like you wouldn't be limited in graduate study options in Humanities fields if you stayed in Commerce and just completely arts breadths in areas that you are interested. On the other hand, Arts does offer an economics major which could allow you keep up that area if you stay in Arts. Economics is the one area in your interests that has noticeable opportunities in industry and government. Ultimately you want to think about what else you would be comfortable doing in the off chance that you have to wait for an academic position. Don't think that Arts will limit you to either getting into Academia or bust though, there are plenty of things you can do after Arts, but just realise they might not be directly or even tangentially related to what you studied.