Concerns about running a kingdom – Love & Improve Life

So I just got my kingdom running (sort of). I took it over from Vaegers and assigned castles and towns to some companions.

Don't really know what I'm doing, so I did some research. Turns out, I assigned feifs to the wrong companions there…

Also, I'm having some trouble with right to rule.

I was wondering if anyone can elaborate on a few things to help me out:

Right to rule. Every time I want to send a companion on a quest for me, s/he says that another companion was sent out and it's probably better to wait a while
Vassals. I know how to create them, but how do I strip one of my vassals of their title – kick the out so to speak?
Feifs. Assuming someone in my kingdom is a vassal that I like, how would I remove their feifs from them (essentially, give them back to myself)?

Any assistance will be greatly appreciated

Right to Rule: In the Reports menu there should be a party companion status option or something like that. This will tell you if you've already got a companion away promoting your right to rule. You can only have one companion doing this at any time and they can take about a month to complete this task.
Vassals/Fiefs: are handled through your Steward, who normally resides inside your primary holding (and can also be a companion). They can allocate new fiefs to your existing vassals and can also strip them of their fiefs too. I don't believe you can outright kick them out, but a disgruntled vassal will leave your kingdom for another.