Wow… i was MIA from this thread for like a day and it has generated so much drama… thanks to the original poster. Bhenjee … to me it looks like you are looking for some bollywood ish to go down. 
You asked for suggestions on how to deal with your sister influencing “situation” and YOU GOT plenty of suggestions… all of which you threw to the side and claimed that we came from a “certain type of families”. Which to me, insinuated that we the whole lot of us are liberal minded and stray from culture (since after all … you pointed out this has nothing to do with islam). You asked for opinions and you got them…but you already had your mind set about this “situation” and once you realized people were not giving you the same opinion/advice as you had in your mind, you started judging us and felt the need to start defending your points. Dude - there is nothing to defend. You asked for advice and opinions and that is what you got. Deal with it.
People generally are not agreeing with you and I have a hard time believing ALL of us come from similar backgrounds and have the same mentalities. I know for a fact we don’t based on responses to other threads in this forum. So … mabey this should be a hint to we are onto something and you should consider certain points as opposed to stereotyping, attempting to hit below the belt (aka you fortune teller-esque reading of us all being “wonderful DIL’s” 
), and feeling the need to defend your post.
I’m with my girl Mixedbeauty … Other than the baychaari gf being “non-urdu speaking” … im also waiting for what other issues there are. 