Hi jd_jader,
Your question can best be answered by any cruise relief pilots who may frequent this forum. However, my response applies to all your questions (SPIC and IFR).
So, in short Canada does not recognize SPIC (Second Pilot-in-Command for those who are wondering) because per the CAR's there is only ever one PIC, one SIC (F/O) and (if required) then the cruise relief pilots (CRP). It depends on the airline itself as to how the CRP is ranked - I know one or two outfits class them simply as relief pilots and they are able to log the time as FO for the hours they actually sat in the seat [so crossing the Atlantic, they may only get to log 3 hours of a 6 hour flight] - there was no logging of PIC time because there can only ever be one PIC, regardless of whether he or she is on the flight deck or not. Indeed, there is at least one outfit that used to give training to their CRP's to a First Officer level but never actually gave an F/O PPC - therefore, technically their pilots could not even log it as F/O time (although I've been told this may have changed in the last number of years).
In saying that, different companies may have different procedures, so I will not claim that the above applies to all operators. However, I think you would be safer to ask your specific airline and perhaps use the last column on the right (its a blank column for logging anything you specifically want to log but that will not count towards anything) should you wish to keep count.
I will, of course, default to any current CRP who can give you a more accurate analysis - my answer is based off the CARS and second hand knowledge from friends who are CRP's.