Re: are sharara's and gharara's most fashionable rite now?
No, girls have not stopped wearing lengha's. I know many who recently wore one on their wedding. My wedding's also in dec, inshaAllah, in pakistan and I'm wearing a lengha on my valima. It all depends on what you like.
Yellow is not paindu rather traditional! I've seen girls wear all kinds of colors on their mehndi from pinks to blues to reds, greens even white. Again whatever you like it's your big day.
Good luck and congrats!! :)