First advice :
Do not mention your first marriage if IRCC don't know about it will save you insane amount of paper work and waste of time.
PS: just in case they find out it will be Misrepresentation and a BAN for 5 years.
Second :: Mention everything truthfully and keep fingers crossed.
PS. be ready for 2-3 years of processing and that can be lower or higher on your luck.
Third:
Avoid opting for the last point as much as you can and provide other documentation to prove your file depending on which route you opt to go forward with. only other explaination they will ask for definition of separation , remarraige and official divorce and time line alongwith legal explanation and actual timeline of entire relationships. Since the gap between your first and second is insanely close there are extreme high chances for IRCC to take it or process your application with mindset of fake or contract marriage. So please be very careful with route you choose and documents prepared in advance in your defence.
Most important::
"
Section 29(2):- Nothing contained in this Act shall be deemed to affect any right recognized by custom or conferred by any special enactment to obtain the dissolution of a Hindu marriage, whether solemnized before or after the commencement of this Act."
contact some lawyer in India and find out what all you can obtain and get it on paper ( only if the tradition prevails in your community ) and prepare thorough documentation to save your file and most importantly LIFE.
as per my experience IRCC don't give a damn since they never had to face such adversity of living away from their loved ones for them wasted time has no value. they will try and waste as much time as they want.
Should you have anymore concerns please DM me I'll try help as much as i can. Hope i was able to give you some guidance