So, I'm a Canadian and here's my perspective on your issue if you are planning to go to Canada for further education.
How important are my IB1 results? and consequently, my IB2 results?
Well, most schools in Canada that do IB complete one or two final IB exams in your first year. If you have completed a class or two before, these marks will get assessed and added to predicted marks in all of your IB classes AND the predicted marks for TOK and EE. As well, applicants are often assessed by their teachers on CAS; if they believe you are going to complete all your CAS hours and your paperwork, then they will indicate that on your application. So yes, first year certainly counts if you have courses completed. Otherwise, the predicted marks of IB in year two and the EE and TOK will be assessed, with an indication of whether or not you will likely be completing CAS.
I hear that you can get admitted to universities without your diploma, true?
Most of the Canadian universities have unconditional acceptances to university...provided you meet a "similar academic standard" (ie at least come close to getting the diploma). They accept certificates of IB courses, yes, but if you only have certificates and not the diploma, they will likely assess your application differently. I've seen some people go to university without passing IB, but others are not quite as lucky. I doubt they would do that at a place like McGill. Depending on where you go, you can get transfer credit for EVERY COURSE...transfer credit for the HLs only...or a certain # of credit hours so you will get your degree quicker. There's lots of choice. Good luck.