Mohan,
You will not receive any email for ECAS activation. As you said, you should check once a day(If you are patient enough!!!
) to see when it is active.
When you receive your Medical Request, they will attach one PDF file with two pages inside, the first page is exactly what I posted before and it is Medical Instruction and the second page is FORM IMM1017E and they have inserted your information like Name, Address, ... in that form and you will find your 8 digit IME number with its Bar-code in that form too.
I think Medical appointment doesn't need anything special and it can be set only with one phone call and providing only name and family.
I guess, you will receive your Medical Request in November.
For sending your PCC, you should wait until your file receive by your local visa office and then you can send your PCC with courier to that office with a cover letter indicating your UCI & File number.
For doing your medical upfront, I suggest you to wait until you receive your Medical Request because you will get your IME number and it helps your medical result receive by CIC correctly.