I feel many of the incidents of Bidaai are taken from old Hindi movies and also new...
we have definitely seen "taare zameen par" scene in the shlok track...
Anamika Anmol story: there are many, but recently if someone has seen the movie Sirf tum, it followed the concept from there. I can name a few more also..
Sadhna-Alekh abnormal part is shown from the movie Khilona of 1970s...and then normal Alekh-Sadhna from maine pyar kiya...
lets see if others can add more...