Retirement tax questions

You should post an NR4 as a Social Security transaction.

1.  Boxes 16 & 17 are all you will need. 
   1. Enter the NR4, treat it as if it is an SSA-1099
   2. Enter it in the Retirement Plans
   3. Social Security section, under ‘Social Security (SSA-1099, RRB-1099)’.
   4. Then, go to the Deductions and Credits 
   5. Select Foreign Taxes under ‘Estimates and Other Taxes Paid’ 
   6.  enter any foreign tax you already paid to Canada on that income.
   7. For more info specific to the US/Canadian tax treaty, please see http://www.irs.gov/pub/irs-pdf/p597.pdf
2. Currency exchange may not have been updated for 2022 yet, but they will be published here:  Yearly Average Currency Exchange Rates - IRS  
3. There is no TIN for Social Security.
4. You should combine all of the NR4's together.