I hit my reaction limit, so I can only react like this. More Daphne will make things better, without doubt
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Nice
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You're comment about baseline is also what I was getting at - his interactions with almost everyone are kinda falsely extroverted, at first I thought it was incosistent, but now I think it actually makes sense to his underlying character. He's mostly neutral when talking with strangers (Donna, Ben, the girl at the petrol station). He's trying to draw the connection out with people who's known from the past. The people he's comfortable with like Miru and Daphne (and probably Dylan) he just goes with his mood. After the initial awkward moments with Dana, he kinda quickly goes to his more baseline approach, while with Gina, he keeps up the banter because she does. Monica is a difficult question, because when he did her in the kitchen, he was actually into her, and he left her there when he realised he wanted Leia more. So there was attraction, he didn't use her from the start, and they both were into it. I'm guessing he doesn't know how to act around her and keeps putting his foot in it, but he also seems too smart not to realise what his words sound like to her.
I think also, when Willi and Miru talk about their detective stuff, they show their baseline. Miru clearly loves baby talk, but it's part of her play with Willi - but when they're both focused you can see their more normal intelligence levels. So yeah, Willi does mask his personality behind the way he talks with people a lot.
I'd say Helen's accident is recent, but maybe in the months old category. Leia had WZ stored in her phone, it didn't show her dialling a numbe she found written on a piece of paper. And she has Emilio, who is good at finding out secrets with his connections. We have to assume Emilio either got his connections by working with Leia (in which case she has the network to find stuff out) or she's employed him to be her network so she doesn't have to go around finding stuff out. Check through Emilio's reactions to Willi, he's never really surprised. I wouldn't be surprised if Emilio knows things about Willi that he didn't tell Leia, based on the way he said not to make eye contact, and told the girl off for saying Willi is hot. Chances are he found out a lot about Willi while finding his phone number.
So given that Emilio probably has also been around for a while, I'm thinking Leia didn't call Willi at the first opportunity, but at the point it suited her. She knows more about Helen than she says, and she doesn't actually act like she really wants to solve that - she's got another goal for having WIlli there, most likely just as someone external that she can trust, except she's too obsessive and bitter to trust anyone.