If he has a visa that allows him to be in a UK for at least 1 year, then he can ask for his file to be processed in London (country of residence) instead of Pakistan (country of nationality). Be aware though, that even if he asks for London to be his visa office, CIC can still decide to send his file to Pakistan. BUt always worth a try, as London is a much faster office. You can see in my signature the timeline for applicants, and you will note that there are a few applicants noted as "non visa exempt" - they are usually in a similar situation to yours - partners from non-visa-exempt country, studying in the Uk.
However, it depends on how long your fiance has been admitted to the UK for, and how long he will remain there for. As he will need to send his passport to the embassy, if he only has a few months left on his visa, it might make it more complicated. If he has still 1 year in front of him, you could try applying through London (well, send everything to Mississauga, then to London).
You can only apply once you're married, but you can start preparing the files. Get familiar with what is required, prepare everything, and send the file as soon as you have everything. Stage 1 takes about 1 month these days, and stage 2 depends on where your file will be sent to. If London, it takes around 9 months for non-visa-exempt, straightforward cases. Islamabad is much longer, as you already know.
There is nothing to do to speed up the process (otherwise everybody would do it), just make sure that you prepare a complete application, with all forms, signed, lots of proofs of genuine relationship. It will help get processed "as fast as possible".
About you working: no, you don't have to work, but you have to show that you are able to support him. Explain how you plan on supporting him when he comes to Canada. If you are living with your family, get a letter from them explaining that they can host you, etc. put together a plan, show CIC that you have thought about the financial aspect of things.
Then download the outland application package, start reading through and preparing whatever can be done in advance (gathering proofs etc.). Don't do the medicals until you're ready to send in the application (just after the wedding probably), as they are only valid for 12 months - your husband should do them as close to sending the application as possible.
Good luck,
Sweden
