So, I just finished a course at York, marks aren't out yet (the final was today), but eventually, when they are released, will details automatically be sent to Mac, or do I need to request them to send it so Mac can count the course as completed (even though both unis are aware that I'm a LOP visiting student), or...how does it work exactly, mildly confused on how the transcript is handled.

You'll have to request for a transcript from York to be sent to Mac so that they can verify your mark that way. Hope that helps!

You'll have to submit a transcript request to York and ask them to send the marks over to the BHSc office.