Joining Spouse(Principal Applicant) later

I guess, below link can answer your questions 3 & 4.

http://www.cic.gc.ca/english/department/media/notices/notice-prcard-mail.asp?utm_source=e-newsletter-email&utm_medium=email-eng&utm_campaign=eNews042012

For your question 2,

Once you land in Canada, you can finish required formalities to obtain PR CARD immediately and then you may go to UK. When you re-enter Canada, you can carry PR CARD copy with you (if you receive PR CARD by email nothing to worry, and if you (your wife in your absence) receive hard copy, she can send you the scan one). I don’t think there should be any problem, as one of my relatives forgot PR CARD in India during his visit and he returned to Canada, he realized that at Toronto airport. He was allowed to enter without any problem.

For your question 5,

The answer depends on so many factors like where are you planning to stay, what type of house would you like to take on rent, what is the initial period for which you would like to carry fund along with you etc. I guess, it will be a good idea to contact someone (friend / relative) there in Canada. You can also write to http://www.servicecanada.gc.ca/eng/audiences/newcomers/index.shtml to get more idea.

For your question 1,

Generally, it is expected that the full family arrives in Canada together. Otherwise, they may suspect as to why did husband didn’t come and immigration officer may ask questions to your spouse and she would need to explain the situation. I am not sure on this so I would advise you to ask someone who has correct information. As I believe, immigration officers in Canada do understand genuine situations and can let your spouse and kids enter Canada without you after formal questions-answers. Again, you can check the same with http://www.servicecanada.gc.ca/eng/audiences/newcomers/index.shtml