It's the guest room at Janet's house I'm pretty sure.
I think you're right about the room and so it looks like the MC is going to visit Janet, at her home, and have a conversation with her in what used to be his old room when he lived there. I wonder why there of all places? Janet looks at ease, cheerful and happy though. I wonder if the MC might be going to stay at Janet's for some reason and they are getting his old room ready in advance.
If Kaley were away overnight at the same time for some reason, e.g., enjoying a sleepover with Alia at Estero Key, who knows where that might lead or what might happen under such circumstances?
Edit: Here's proof of NLT establishing the presence of 13 sirens instead of the current 12 way before the game even launched.
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Now isn't that interesting as Diana is wont to say. Never seen that before. Is the thirteenth siren Evie then? At the end of the game is she going to step out of her crystal prison, cloak herself in flesh, and become a real woman? Could Evie even be the eponymous fabled treasure of Nadia? We have been given no significant backstory at all in respect to MC's lovely Djiniri. Was she once-upon-a-time a human woman who transformed into a Djinn?
(I remember a story a girlfriend told me a few years ago about a lady who trapped a powerful Djinn and bargained with him for magical powers in return for his release. So to escape her clutches the Djinn changed her into a Djiniri, much like himself, giving her all the magic she had ever dreamt of but only to grant wishes, made by humans, rendering her powers useless in respect to personal gain and self-interested purpose. Wanting to rule everyone and everything she ended up unable to rule even herself although gifted with the power like the gods. Be careful what you wish for, as they say, especially when dealing with supernatural entities like Djinn.)
Or was Evie originally born of fire and has always been a Djiniri? Does she have a hidden agenda all of her own? Some design that she wants to bring to fruition by guiding the actions of others? Is she in any way like, similar or connected to Daemalius? Does Madalyn know about her? Could she even be behaving in the way that she does because Idaho Johnson wished it so before he died? When you think about it we know next to nothing about sassy, fey and funny Evie.
Even though she's not a girl could Evie be the thirteenth girl of Nadia?
If that makes any sense at all?