+ More commoners for Amarr; I'm increasingly hearing that it's difficult to do anything as a commoner character lately because you get walked over by all the (sometimes only-days-old) Holder characters pulling rank on you. Admittedly I'm not exactly helping this with Esna being a Holder and all, but it's still something I'd like to see worked on.
"I do not serve your House, Lord [newbie]."
It depends of the context.
If he asks you to do something for him, then no, you do not serve him.
If he asks you for respect and you are a commoner, you are obliged to do so. It can be very useful when a commoner Amarrian comes aggressively into your character imo.
Do the various houses respect each other? It seems to me that a Sarum loyalists would not think very highly of a Tash-Murkon Holder. Certainly there's room for conflict there?
Sure, you can perfectly hate a Holder of another house. You can even hate a holder of your own house, even if he is not your lord.
At least, speaking against a holder above you in the social ladder while being yourself a Holder might be ok, though maybe not the wisest thing to do.
But speaking against (especially insulting/aggressing) a holder of any house with a commoner status, or worse, sure equals to a high insult, and if you are not a capsuleer, I would wager that the Holder is maybe in his right to outright kill you if you serve him, and if not, asking for compensation from your own lord, which can probably mean death/slavery/whatever, unless you are really valuable...
I too think there is room for conflict, being going openly against someone of higher status is of course possible, but probably not the wisest thing to do in that case. I am pretty sure that in the Amarr Empire, one does not just cross the divine social order like that.