What creatures in the DV get a threshold?
I think this goes back to the old question of what creatures have a soul, and keep in mind that a lot of this has no reference, it's just drawn from actual lore and my gut. So:
Shapeshifters: maybe
wereforms other: maybe
Depends, are they mortal (or at least part mortal)?
lycanthropes: maybe, likely yes
hexenwolves: maybe, likely yes
Definitely yes to both of these, however they both have lifestyles/activities that would hinder a threshold's development.
loup garou: yes (he is usually ~human~)
He definitely has a soul. For whatever reason I'm unlikely to hold his inner monster against him. It's not like it's his choice to do these things.
critter-were (example wolf were tera West): maybe...likely no
That is a weird one. Honestly I'd lean towards yes, for the same reason Thomas gets one. Also I just like the character.
denarians: I have no idea
The host: Yes, though again, lifestyle/activities.
The fallen: No, definitely not.
Scions: maybe - in most cases yes
Almost always yes. I don't think they have the same option as the changeling. Even if they choose their supernatural heritage, I don't think they can ever be fully that, so I think they are always at least a little mortal.
dragons: maybe, likely no
Yeah I'd go probably not on that one too.
Do true beleivers have their powers removed while in thresholds if not invited in?
Technically yes, but it is a bit weird.
Can a threshold be used to keep things in?
My inclination is not a standard house threshold. They just aren't made like that.
Do items of power weaken when brought across a threshold?
I'd say yup.
What strength should a sunrise have? Seems to obliterate ghosts and spells (depending upon duration) - so it should be pretty strong.
It's strong as long as you don't have a piece of meat to hide in. It's not going to effect BCV or RCV for example (other than the actual light of the sun of course).
When in the nevernever - if there is a residence can it have a threshold? if so, does that mean creatures of the nevernever can have thresholds (at least within the nevernever)?
Hmm, that's an interesting one. My gut says no, because it doesn't have soil to grow in (both metaphorically and literally).
Can/should a demense have a threshold?
A Demesne should have it's own unique protections. I'd say no for the threshold.
To go along with the above post of mine: What qualities are required by a being to have a threshold? Sentience? A soul? Surely, it is not a matter of good and evil.
Yeah, I'd go with a soul.