Tangle, you grab the girl, manage to disentangle her from the rope loop, and pull her clear of the gas and the mushrooms. She sobs, and embraces you, clearly terrified but seemingly unhurt.

Soar makes sure the long branch falls to rest outside the circle without touching mushrooms, and then helps Tangle calm the girl. "It's okay. You're out of there. My name is Soar. Would you like to come to our campfire and have some food? Warm up? Figure out where you want to go?" She nods to Tangle, freeing her of the burden of trying to comfort this girl, but also giving her a serious look paired with a glance around the forest to give the area another pass to ensure there aren't unseen others around. 

Persuasion: 18
Insight to try to see if the girl seems to be holding something back: 13

If no alarms, she'll lay on hands for 5hp to either cure a disease or neutralize a poison, whichever seems more reasonable.

Tangle gladly extricates herself from the girl’s grip, looking… stricken? She nods and hurries into the woods, stopping once she is out of sight to gather herself.

Then she does a slow and deliberate scout of the area, trying to make very sure this is an isolated ring of magic mushrooms and there is nobody, Fey, dragon, or otherwise, lurking in wait. She’s also looking for answers as to where the girl came from, or what she was doing out there. She does so quietly and carefully and takes her time, the better to not be back at the campsite. If she discovers nothing, she returns an hour later.

Stealth (w/Adv): 27

Perception: 32

Investigation: 9

Eventually the terrified girl calms down and manages to speak:

Yes, yes, Soar, thank you, thank you.

Soar does not get the sense that she is holding something back; she seems genuinely scared and confused.

Tangle, you spend a good deal of time searching the area; you do not find any trace of a creature lurking in wait. However, you do notice an unusual metal token, dangling from the branch of a living tree not far from where Soar picked up the branch that she used. It's a metal disc, reflective almost as much as a mirror, with a hole through the centre.

Tangle will take the token, with the intent of bringing it back to camp with her to show the others.

Suddenly, a lithe monk lacking hair and with a green sword strapped across his back appears. He asks Where am I?

Soar uses her opportunity while laying on hands to also examine the girl for any medical condition, any oddity, any markings, and any possessions that might give a clue to where she is from, who she belongs to.

Investigation: 11

Assuming nothing odd, she'd walk with the girl toward the campsite, offering to carry her if she wasn't able to do it on her own. Her guard's starting to drop, but she's still alert for any sign of deception or pickpocketing. She believes the best in people but she managed to get through years in Waterdeep without losing everything she owned to thieves. 

Before she arrives at the campsite she will call out to the boys and warn them she has a guest, and that Tangle is scouting.

Soar, you don't sense that anything has changed when you lay on hands; whatever has affected the girl, it's not a disease or a poison, as far as you can tell.

When you try to inspect the girl more closely, she pulls away instinctively, and looks at you with some distress, but calms down. However, she won't allow you to search her further.

Bazavur and Jalt, you hear and see the approaching Soar with a small figure you do not recognise.

"Do you have a name I can introduce you with? My friends are nice. Would you like to know their names? And I was only trying to help find anything about where you come from, little one, and if you are injured. You get to tell me how much you are comfortable with, of course. I am a paladin of Kelemvor, and can heal you and cure you of disease or poison, if you wish. And if you have ideas of where you want to go, share them when you're ready," Soar says. She gives her space. (Is she able and wishing to walk on her own? Is she limping? Capable? Confused? When they gets closer she says to the dragonborn in the camp: "this is the little one who was crying for help. She seems to have lost her memory thanks to a patch of enchanted fey mushrooms she was trapped in. Tangle is scouting around a bit more. Jalt, maybe you can help her get better, or learn more about her story? Bazavur, if you have ideas, I'd welcome them."

Tales from beyond(trying out my new stuff): 3

(So that indicates this result:

Tale of the Beloved Friends. The target and another creature of its choice it can see within 5 feet of it gains temporary hit points equal to a roll of your Bardic Inspiration die 4 + your Charisma modifier. (2))

Bazavur pulls out a candle from his belongings and begins spinning a tale that seems like it’s entirely probable to him as to why this girl is out in the wilderness alone. At the end of his tale she would feel a bit better and Bazavur adds “If this story were to be true, and I’m not saying it is, where then would your friend be I wonder.”

I'm sorry, I don't remember my name or how I came here. I don't know where I'm from. I'm really sorry. The girl starts to tear up, but swallows hard and tries to look brave. I don't think I'm injured. And I'd like to meet your friends. I wish I could tell you a name, I really do.

She sits down by the camp fire and seems to calm down under the influence of Bazavur's magic. If you have any questions, you can ask - she seems willing to answer, though unable to recall much of any use. She doesn't seem to know anything about herself, and though she looks through her pockets at Soar's request, she finds nothing - no possessions, no money.

Bazavur, the girl thinks really hard, but as the magic fades she frowns and shakes her head. I wish I knew. I don't remember anyone at all.

When Tangle returns, she will show the girl the shiny token. “Is this yours?” she asks, not unkindly.

As Bazavur asks his question, or when Tangle asks her question, Soar takes off Hazirawn and sets it down by her tent. As she does so, she casts detect thoughts and skims the surface thoughts of the girl. Just to make sure. Assuming it's nothing, she'll help with dinner, serve up an extra portion for the girl, and then insist on full watches overnight, with everyone keeping an extra eye out on the girl and elsewhere. Candelabra will do sweeps around the camp all night and report back anything odd. 

"Those mushrooms were strange. Almost out of nowhere. I've spent a lot of time in the city, so I don't know these things, but they seem rare. Tangle, any ideas? I thought they had fey magic on them. How'd they get there?"

Tangle, the girl stares at the token, then shakes her head.

Soar, what's most on the girl's mind is fear and confusion; she seems genuinely not to know where she is or even who she is.

Tangle tucks the token into a pouch, and watches the girl a moment. “Gwen means girl in the elvish tongue, but I know it is a name in the common speech. Will that do for now, until you recover your own name? Every creature deserves a name.”

Yes. Um. Thank you, the girl replies.  She looks a little encouraged, or at least less despondent.

"Gwen works for now, until you remember yours," Soar says. She tries to converse with her in elvish a bit. It's a bit stilted because she doesn't use it much, but it's serviceable. She is beginning to trust this girl, and feels bad for her. She tells her that they are going to go stop something dangerous deep in the Misty Forest, but that if she wants, she can travel with Soar, and Soar will try to get her to some elves where she will hopefully be safe. 

She's willing to take responsibility for the girl, letting her ride with the group the next day, if she likes. She suggests Jalt cast greater restoration or something before they go to sleep.

Tangle nods like it's a done thing, and stands up. "We cannot take Gwen with us to fight... to complete our task. It is too dangerous. Can one of you contact someone and get her safe?"

edit for concurrent posts...

"The elves are a good idea, Soar Jestalle."