I'm a bit surprised she chose to get a house that's in the forest. I'm not sure about the safety, but mostly they've used a carriage to get there, so what exactly is her plan when she needs to sell her wares or buy ingredients? She won't have a carriage herself, so she'll need to walk to the city and then back. I guess that, if the forest is relatively safe in terms of monsters, she might be able to get ingredients easily for her potions.
She does have a fairy friend now so maybe she can help her.
Hopefully Rei's not it, though, after Kaede took to her as well as she did.
That would just be strange considering all of the help she's provided Kaede up til now; she just seems like a friendly person. Rei is wealthy too and it's from hard adventuring work so I can't imagine she would scheme something for some benefits. Considering Kaede's potions are essential for Asul, a member of the party she leads, it would be absurd to antagonise her. Even if Rei's good treatment of Kaede was strategic, by trying to get her good favours in order to ensure good deals on her potions later, Kaede doesn't have a merchant's greed. She's been selling her potions cheaply and basically gave away the hi potions because she hadn't gathered the ingredients and had been paid with a purifying stone (which was worth 90 potions).
Honestly, it seems to me that Rei has heard from Asul that Kaede is prone to getting high-balled and just not very good at asking for proper payment for her skills so she's doing what she can to help her. In general, Rei also probably wants Kaede to get settled comfortably in the capital, because the sooner she is, the sooner she can start doing business again.