Most papers will be ten to fifteen pages long, excluding bibliography.
Quality is more important than length.
You may include graphic elements in your final paper, such as maps, illustrations, charts, etc., if appropriate to your topic. You may choose a topic of general or popular interest, like a popular sport, but you may focus on, say, the ethics of recruitment of college players. Be cautious about biographical topics. I won't give you a minimum requirement, since how many sources you find and use will depend in part on your topic. Try to make some choices even before submitting your preliminary bibliography.