please define conservative personality

But no, it wouldnt create any problem. at most a question about it might be asked like;"do you observe it of your own accord or were you forced to wear this (abaya/scarf) by your family"?

as for your second question, again, no,your dress has no bearing whatsoever on group allocation..(unless someone turns up in totally inappropriate clothes leaving nothing to imagination, in that case candidate's 'moral character' might be called into question )
though i did hear a rumour that former chairmain fpsc late jamshed gulzar kiyani once made an exception for a veiled female, by writing on her report "not to be allocated in FSP" (or something to that effect)..but again, it could have been her oral response to some question instead of her appearance...seniors who appeared during JGK's time!!, plz confirm this