This is just a general question that is more about RPG preference rather than mechanic:

1) What is the general consensus on what family of a character's clan would be the Daimyo they serve. In short, would a Hida serve under a Hiruma Daimyo?

2) How involved should a Daimyo be with the PC once they have entered into another service, such as the Emerald champion and has anyone really brought that up in a campaign?

Thanks in advance

1. Yes, it's quite possible. I know they are named Families but they are really just another clan inside a clan. So it's possible for a Hida to serve under a Hiruma.
2. So, if players become Emerald Magistrates, then, yes, their immediate lord actually becomes the Emerald Champion (or a senior Magistrate, most probably) but they still have loyalty to their clan and their champion. Of course, serving 2 masters is indeed hard, so their loyalties might become a source of strife (totally intended pun).