I can answer about the testing part. Although, the travel.gc.ca website says you need RT-PCR, I know of people that got the RAPID PCR and it was acceptable to Canadian authorities. If you call air canada, in the auto generated voice recording, they mention both as being acceptable.
Time to reach in advance depends on the test you choose. I would say give 3-4h for RAPID test and 8-10h for RT-PCR.
RAPID test is Rs 3500 , but RT-PCR is much cheaper (300, i think)
For testing, all you would need is passport and tickets, I think