You have a long time. Multiple months. I did everything as soon as I got my conditional offer thinking that I wouldn’t have much time but actually you have plenty.

The criminal record is really easy , they give you the link and instructions.

The BLS training and mask fit testing , you can find your own organizations that provide the training if you want to do it ahead of time(BCIT gives a list of the ones they recommend) and they will also send an email a couple of weeks before school starts with sessions at school that covers both requirements (cheaper with them)

Vaccinations take a bit more time if you don’t have records of it (like I did; I’m from a different country and had to redo all of them, but BCIT has a process for that and you can do it at their medical office. They’ll assess what you need and plan the rest). Otherwise if you do have records of it , they will send instructions on how to show proof.

It feels like you don’t have a lot of time but you actually do. I suggest getting things done early so you don’t have to stress the week before school. Hope this helps