Hello. I might be starting a game soon and there is some things that I need advice on. Mostly about thematic rules, because I am going to try DFRPG Fate Core which hopefully causes minimum amount of head aches.

1. Thresholds, if coming in uninvited:
* Blocks all kinds of spellcasting.
* Blocks other active powers(Glamours, Incite Emotion, Domination etc.)
a) Passive effects? WCVirgin, werecreature or changeling Speed/Strength/Toughness etc. Any effect when entering or inside? Any difference on are they always on or limited by shapechanging or feeding dependency?
b) Owing favour to fairie, unspecified when or what, fairy comes to collect and no other intentions. Does that count as invitation? Can that fairie do that stab-your-own-hand-if-refuse thing that Mab did at one point?
c) True Faith abilities. Probably can get in just fine since mortal, but using these while inside?

2. Exact words trickery and fairies. How would you think about these:
a) "I am willing to consider if (insert favour)." After favour willing to listen but since no actual promises made, can just say no after some discussion.
b) "One favour from (plural) you." While pointing all of them. From fairy's perspective that is one favour from each.
c) If players try to negotiate about favour, promising not to ask anything dangerous for them. Then ordering, not asking, them to do something. Or just pointing out that according to fairy's judgement, favour should not be dangerous. Or just trading the favour(s) forward to another fairy that is not bound by first ones promises.
I ask because while I want to drive home the fact that fairies think literally and differently than humans, I really don't want to be a dick.
Players have not read the books.

Other questions might come later.