I think this year's BB is confusing when it comes to analysing specific roles. Last year was so easy, almost too easy (Dean and Elizabeth as mummy and daddy, Brian and Helen as the kids etc).
In the rich side, Alex and Adele definitely do seem to take on parental roles. Alex may be reluctant, but can't be anything but dominant - it's his way, while Adele, I get the feeling, is accustomed to being 'motherly' as the eldest of many siblings.
Jade loves her 'babba' role while PJ seems to want to be the adolescent male; trying to be mature and responsible but liable to failure (and easy forgiveness). This is a great role if you can capture it - I think Paul in BB2 took this on, and less convincingly than PJ to date. (Although it does open the way for reprimands from 'higher' family members and the teen-boy can promote rebellion). PJ is possibly lucky too, in that 'baby' Jade, despite her record for histrionics-on-tap, seems much more sexually precocious and less truly vulnerable than Helen did. Hence PJ is less liable for moral censure in his behavior towards her.
Kate was clearly an alpha-female character, but will now be directionless as her 'prince' is gone. I am interested to see if she now forsakes Jonny, who has been her closest playmate (even a friendly surrogate for Spencer when he was still in the house) and moves on to the security of Tim, who clearly wants to be a leader and has the huge advantage of strategic information from his watching the show beforehand. Tim can be amusing and charming and says all the right things, but he is ruthless and will do what he sees as necessary to win. He will test existing relationships to the limit before this show is done, and will certainly test the group's subliminal perception of Alex as the 'leader'. I'd be surprised if he didn't make use of his sojourn in the poor world to forge a strong role for himself, and will be a false comfort to Kate and a 'friend' to the estranged Jonny. For all that, Tim doesn't strike me as a 'natural' leader in the way Alex does, but his greater level of cunning (Alex often demonstrates a scary lack of interpersonal awareness!! He really does see only his own little world a lot of the time I think, unless it's world issues etc, when he's often pretty good) - Tim's crafty intelligence will serve him well for a while, but could prove to be his undoing if loyalties to Alex are strongly maintained or Alex wises up and decides to actually wield his own potential power. If Jade (or even Adele) was evicted - likely to happen soon-ish - Alex could be in big trouble.
Jonny is a tough character to work out, because he was deprived of the paternal role he probably gravitated towards, from Day One, by a higher 'patriarch' in the form of Sandy and then by the emergence of Spencer and Alex as co-leaders. His stab at parenthood (in concert with Alison) clearly failed, and he has not recovered. His role as court jester wore thin too quickly too. He is left as a 'kindly uncle' comforter of fellow-strays - Kate, even Sophie - but this means he shouldn't be wholly written off, even though he is vulnerable to attack in his position as the failed side of the family. He can also engage public sympathies. He is in greatest danger if Sophie (very likely) or Kate is evicted, and needs to swiftly befriend the likes of Adele, to ensure he is re-assimilated into the fold. However, his antipathy towards Alex means he is more likely to bond with Tim. This is a really tricky time for Jonny! HIs best bet is probably to stay 'kindly' and calm, and court public appeal as the friendly uncle-outsider.
Oh dear. Poor Sophie. Well. She has become extraneous to the group and it is getting painful to watch. I wish her parents would get her out of there, fast. She really has no-where to turn. She might semi-bond with Kate, who is feeling similarly low, but I can't see that as a real, trusting relationship (not cool enough for Kate, basically, even while she is in such dire circumstances). Uncle Jonny is her best haven, but he can't offer her any real protection. It is a disaster for Sophie that Tim dislikes her so much (based, it seems, as much on his realising public opinion of her), and she rebuffed Alex's attempts to assimilate her last week, a truly stupid move. In an ideal world, Sophie would have liked to be the alpha-female or even a mother-figure - ie: with power. In cave-society, you get the horrible feeling that this group would have deliberately discarded her to fend for herself by now, to ensure she didn't consume precious supplies. I think this is also why her mere existence - especially when in the rich house - so deeply outraged and offended people (particularly Jade because she is too immature to see beyond survival issues, and lacks compassion).
SORRY THIS IS SUCH A LONG MESSAGE!!