RF I think there are different types of Pakistanis settled abroad, and you can't discern general trends on the entire diaspora of Pakistanis settled abroad. There are no social constructs as such, even in Pakistan there aren't.
There are those who went from the rural areas as whole families, still maintain joint family systems abroad, then you have the kid who went abroad as an international student in undergrad, the adult who went as a grad student, professionals who went abroad for jobs, families who moved as a whole...etc...
Within these too, you can't discern concrete trends...people come from different family/ethnic backgrounds, have different personalities, go through different experiences abroad, and evolve differently...
Many of the educated Pakistanis abroad seem to be very left-leaning, way more left-leaning than the average Pakistani public or even the educated conservative Pakistani crowd back home. Honestly that always puts me off, its like they've lost their self respect in their mission to be politically correct. In Pakistan, the average Pakistani is more rightist in their political outlook.
Halal / Haram food, again, most Pakistanis abroad I've noticed will buy halal food for their homes, but the second generation kids might eat non-zabeeha if they eat out. Many first generation Pakistanis who went abroad at an early age also eat non-zabeeha from like KFC or Mc D's. But there are exceptions to this too.
Dating...I've seen that many Pakistani parents settled abroad are open to the idea of their kids dating and looking for their own spouses once their kids reach college age. The trend about this back home in the cities is changing as well. There are very conservative parents too who insist on importing spouses for their foreign raised kids from Pakistan.
The example you mentioned abt the guy being a player on campus but turning into a shareef dude in front of his parents, I've seen kids of all types. There are many boys who do what you described, but there are others too who do what their parents would like to do, and many times parents themselves don't strictly mind their boys dating.
Revealing attire...I've seen fob Pakistani girls in mini skirts in the US...and I've seen first generation Pakistani girls wear quite revealing clothes. There are others in hijab and jilbab too. So again, I think there's no real trend. But I think mostly, Pakistani girls dress quite modestly.
To be honest, the one and only thing that I see unites Pakistanis abroad is not their thinking, their views about Islam, not even Pakistani music....but only PAKISTANI FOOD. I don't think you'll ever find a Pakistani anywhere in the world who'll refuse a plate of good Pakistani food.
*Nadi * you're right yaar gay rights is something that Pakistanis as a society are not going to accept for a long long long time. Yet, I've met Pakistanis who as individuals don't have any problem with this concept. They might not consider it for themselves but they don't have a problem with it. There are gay Pakistanis too, in Pakistan and abroad too.
IMHO the way Pakistani society is set up, there is a deep dichotomy between what happens and is acceptable at a societal level and the image of Pakistan, and the day to day realities in people's lives.
For example, you'll be surprised how many women get their babies aborted from seemingly traditional families. But you'll never see a program on PTV condoning abortion.
There's alcohol consumption going on at every level of Pakistani society but people like to keep it hush hush. You'll never see an alcohol ad on TV. I think this is because the Maulvi brigade still holds strong sway on what happens at national level [Thank God for that! Atleast we don't accept and propagate social levels. At a national level we still acknowledge they are wrong.].
There are Maulvi's who drink too. There was a maulvi who used to be called Maulvi Whisky, if you guys recall. He is not alive today so I won't name him.
Dating, Its not exactly the western form of dating that goes on in Pakistan, as in going to movies and restaurants, but pre-marital relationships abound, specially among cousins or neighbors, and parents are very much aware of it too, that their son or daughter like that cousin or that girl/guy in the mohalla.