Casting coup, sending brains into a tizzy, premier period film, plot set in a bygone era

It's a casting coup... that's sending brains into a tizzy. Reportedly, Vivek Oberoi has been pencilled in for Mani Ratnam's 'Azaan', which is to be helmed by his former assistant Shiva. And word has it, that although Ranbir Kapoor had earlier consented to 'Azaan', he bid a hasty retreat on realising that the opus wasn't going to be helmed by the South Midas touch director.
A close source, however, has a different tale to tell... and asserts that Ratnam is well settled in the director's seat for 'Azaan'. And that Ranby Boy too is part of the project, athough the female lead is yet to be finalised.
Furthermore, MR's not ruling out casting any new finds, either. Incidentally, 'Azaan' will also be Ranby Boy's premier period film, with its plot set in a bygone era.
The Vivek Oberoi project? Reportedly, it's another venture altogether! Titled 'Pakhi', this one's helmed by Shiva. Right, Mani sir?

Please explain to me the emboldened parts.
Though I know "tizzy" means "confusion", "bygone era" means "Past days" and "plot" means "story of a film"
Source : http://in.movies.yahoo.com/news-detail/87553/Mani-Clears-Chaos-Casts-Ranbir.html