Okay so we have this so far
My role | Your role
Sherlock Holmes x Irene Adler & & & John Watson x Mary Morstan
So we decided to have them all meet prior to the films. Our best bet would be to refer to the first film as it gave the most information on Irene and Holmes, and Mary and John. I also do think it might be better to develop the men and women together, before throwing them all together so the strain wouldn't be so hard and it wouldn't undo anything. It's also possible to create some kind of case to do just that, perhaps Mary and Irene do witness some murder and need protection, Watson stumbles across Holmes and the two team up to help the ladies. Just a suggestion, there are plenty of ways to tackle this. I also wonder how we can give Adler and Mary a connection to the two boys. Holmes would be surprised to find someone as clever as he, though I was wondering if perhaps Mary had taken an interest to becoming a nurse or something like that. It also might be cool to use "love letters" in the story if the pairs are ever separated for some reason.
And about how much do you feel up to posting per character, you think?