Thank you very much for your prompt response. It is very useful. Really appreciate it.Well, Indian consulate was least helpful, i ended up calling high commission in ottawa and they said the grace period of 3 months is not for travelling to india but other countries for which we might have visas on Indian passport. For India they said you can get in trouble with immigration, they had no sure answers and the conversation was full was 'mights', 'maybe', 'could be', 'very likely'. But in the end they recommended surrendering the passport and then travelling by applying eVisa. once you have your oath, you can apply to surrender right away and it takes around 7 business days to get your surrender certificate in the mail. I think in the meantime you can go ahead and apply for eVisa. But the only thing to make sure is, you must have eVisa and CDN passport before you enter India, no matter what.
As far as rescheduling the oath is concerned, you could always do that and then see when you turn shows up again which could take a while.
For me personally, the oath got scheduled at a time when i was back from my India trip, hence i did not have to worry about the mess. But just followe the rulebook when it comes to Indian embassy, anything out of way could only make things worse.
I am planning to wait until April for oath invitation. If I don't get it by then will apply for PR Card renewal and postpone my Oath if it comes after April.