u don't need to show ur research interest when u apply if u don't have several paper in hand, u only need to show ur smart, intellgence, hard working, which comes from PS and RL, the latter is the most important
Corporate finance.. It is related to accounting, but not an area. I guess you want to focus on capital market research. Read Kothari's 2001 review paper. Although it is an 10-yr old paper, it is still quite helpful for beginners.