You are free to PM each other as you please. The original game even made it necessary to *gasp
* go behind the GMs back sometimes!
So while you have
to send me a PM and ask if you know a poison maker in the city or if you can conjure one up, you don't
have to tell me who you are planning to use it on. Ooops, poor Duke, seems he was poisoned...
The families are very tightly knit together and yes, you probably know all the personalities of the important family members. Your discretion is what determines if a family member is important or not. As for the rivals and independents, not so much. But there are those who can find out, for a hefty price. As to if you know
who these people are, again, discretion is advised.