Although I have yet to finish putting together where everything in the Catacombs is beneath. I have found something quite interesting to note. The burial chamber with the statue heads is almost RIGHT beneath a statue of Balthazar.
If anyone else would like to try and put together the Catacombs, by all means, go for it. Though if you think the exits will be exactly aligned with the surface entrances you're wrong. It's really odd about that..
Anyway, I'm going to see if I can finish this...