After the finale, I'm certain Jo and Danny aren't siblings and that Janny is endgame, and here's why.
After their scene in 1x7 last month(https://www.youtube.com/watch?v=osRi-CONT-M), someone posted this; "No way. Can't be siblings at all. I think he just puts Jo on an untouchable pedestal because he does not want to lose her. She's the only one who's always there for him. So he vows not to screw it up by getting in a relationship. But boys are boys and Lacey is very pretty. So he takes that 'frustration' and turns it loose on Lacey. Lacey was his first kiss after all. But I support Janny. It's much more romantic and healthy."
and then Danny says the same thing during the park scene in the finale(which was really raw and natural by the way. madelaine is such an amazing actress!). A romantic relationship for them is more than possible, I think. I can understand why Danny doesn't want to risk their friendship being put to an end but I can most definitely see him realising that Jo is worth the risk later in the future.
I don't want them together now. I'm glad that he didn't kiss her, or tell her he feels the same way or anything like that. No. Their relationship wouldn't make sense or be real if it were short term, as Lacey and Danny's is. Their feelings need to be explored and drawn out before anything happens. The anticipation, the build up between the two of them is amazing. And that's why I personally love their relationship.
The scenes they have when they're just talking are so intense. Danny left and now Jo will explore her feelings as will he and that really just adds that extra dimension that Danny and Lacey doesn't have and now, never will. On to Danny and Lacey..
I can't get into their relationship. I can understand it, the feelings they have for eachother, but it doesn't seem real or romantic to me. It seems like it's just a crush and it doesn't have enough power to grow into something more. It went too fast and skipped the friend zone. Lacey didn't trust Danny and then she did. Maybe if she were a friend to him for two seconds before she was his girlfriend, I'd feel differently but to me there relationship just is. It's there, it exists, they have feelings for eachother and everything but it lacks foundation, depth and friendship. Maybe it'll change. It has some potential to change, maybe. It'll take longer because I feel their friendship needs to be explored before anything else , so it'll be a awhile before anything that actually has a sense of realism in it happens. I don't know.
Now, this secret Danny is protecting than Jo from?? I have no idea. I'm sure it has to do with her family but nothing to do with them being siblings. Danny is still crushing on Lacey. He knows those feelings won't just vanish into thin air. He wouldn't let her continue to feel for him knowing it's inappropriate, whether he's trying to protect her or not. She asked for the truth that surrounds their relationship and he gave it to her.