I talked with Tatters about Constance possessing Excalibur. Although she has it, it can't be drawn by her or anyone else at the keep. You'll need to quest to find a way to use it, or find the person who can use it (which may be Arthur). Constance is the one charged with making that selection and may grow into being the Lady of the Lake in the narrative. 

[quote=@stveje]
* I assume I'm part of someone else's household. Is the household and the keep the same? I'm not sure how households work.
[/quote]

Yes. The stronghold has a lord (which I'm just going to start calling a duke unless somebody says they really want to have a petty king instead). You're part of that lord's household. If someone picks the keep liege (which is looking unlikely) that lord would be a PC, otherwise an NPC. 

[quote=@stveje]
* I chose the right to "step out of your earthly life" because it seemed like it might be the best fit for her people's space/size-changing abilities. Maybe it's not so much changing their size or shape as stepping into another space or navigating the in-between worlds. If that makes sense.
[/quote]

It does. You have freedom with that Right to make a selection of what that travel you want, and if you miss the roll, I'll select an appropriate response for your destination. I like this direction for it. 

[quote=@stveje]
* It says a staff is 3-harm, but that honestly sounds a bit high to me. I'm thinking like a regular wooden walking stick/staff. 
[/quote]

You probably want to keep this. Mechanically, all the primary weapons are 3-harm because that means you're evenly matched with NPCs or monsters wielding similar weapons and wearing armor. You can still flavor it as a walking staff and the Outranger as especially skilled with it rather than merely strong-arming with a deadly weapon. Considering the outranger might be one of the people most likely to encounter dangerous creatures, I don't think you need to mechanically weaken yourself to flavor the character the way you want. 

[quote=@stveje]
* Do you only pick one "defined by" for a people, or can you pick more than one?
[/quote]

You'd only pick one in this main category. It looks right on your sheet.

[quote=@stveje]
* I chose numbers for a small vassalage, but maybe they have fewer than 40 warriors? Maybe a bit less than 300 people, too. Like, 200 people maybe. Thoughts?
[/quote]

I don't think you want a vassalage, unless you intend that the halflings are actually structured with multiple families swearing formal oaths of fealty to a lord. What you probably want is something like a clan or an enclave to be Nin's People, representing her family, friends, and relatives who care about her personally, with the understanding that there are several such groups of halflings such that there are many hundreds of them total.