You're doing good work!  Understanding Catholic marriage laws and how they mesh with civil laws is a daunting task and in many respects does not produce clarity, if only because it can't!   But whatever you can pick up by studying the history of marriage, particularly in canon law, will, I believe, give your collective efforts a big boost!  It's not easy, but I'd predict that you will learn a lot while you're having lots of fun!  The two CLSA commentaries on  the 1983 Code of Canon Law are useful resources, if not indispensable.