Where can I do an FAA IPC in Canada?
You will need to find a US CFI-AI who can perform a competency check for you.  It can be done in the US or in Canada (in a US registered aircraft unless that CFI holds TC and FAA credentials).

If you are within 6 months of being current, you can do approaches with a safety pilot in Canada. If you are flying a US registered plane, then you will most likely need a US certificated safety pilot.  If you are flying a Canadian plane, then your safety pilot should be a Canadian pilot, acting as PIC for the flight.  You could still log the approaches and simulated instrument time.

In my experience, it will be far easier to find a US CFI in Canada than it is to find a Canadian CFI in the US.  Ask around.  Consider contacting an organization like AOPA if you are a member, or COPA, and asking them for help locating US CFIs.  I would also ask if they have additional guidance because they may have letters from Transport Canada and the FAA which may have policy considerations which might be good to know.