She seems to be either a green Hag, or an annis Hag, which are both fey (it's only night Hags that aren't true fey anymore). It depends on what kind of archfey you're pacted to as to how she would act, as Hags aren't necessarily part of any of the courts and tend to form their own covens or groups.
I wish there were more options for pact of the chain, as we don't even have all the options that we should have yet, becuase we don't have pseudodragons or sprites as an option. I'd love it if they added even more, as I've played in several games where people had creatures other than those as their chain-pact familiars. There are a lot of little monsters that fit into the 1/4 to 1 CR bracket, but unfortunately redcaps aren't one of them, they would have to make a weaker version available to summon.
