Q #1: No. The PPL will be a straight trade across. There will be an air reg.'s test involved, but it is lightweight. The Licence here is a cross between JAR and FAA. Not as difficult as the JAR, but more so than the FAA. How Canadian, a compromise.
The actual flying is second to none.
Q #2: I don't know if it is a straight trade for the medical, but it is very likely. You will need a Canadian Cat 1 Medical as it is the validating document for your licence. I would contact Transport Canada at
www.tc.gc.ca for that one. Follow the links for Aviation.
Q #3: There is a lot of hiring by the majors right now. They are hiring all the charter guys and creating openings all the way up the food chain. That's the good news. I don't want to discourage you but I also don't want to mislead you. It is a difficult road for the low time pilot to walk. Much of the hiring here is based on family and friend connections. Not all of the hiring, but a lot. The next thing that will affect you is where you are willing to work. The more remote, the less competition you will have. Lastly, you will have to show up in person to these remote locations and pester the crap out of the operators until they hire you or get a restraining order. It will likely take multiple trips to remoter communities. Be aware, remote in Canada is something I don't think most people from Europe or G. B. can grasp until they see it. We will, and often do, drive 8 or more hours in our car on a long weekend just to get to a beech. Then drive another 8 or more hour’s home. In Europe, you will have crossed 3 countries; here you are likely still in the same province.
Personally, if I were going to do a float rating I would do it here. There is a school in Kelowna that offers an excellent course that shows you all the bush stuff and can be applied towards your commercial licence (two birds, one stone). You learn to fly in the mountains, in the bush and off small lakes and rivers (I am going on what I have heard and read... do some homework to make sure I am not leading you astray and that they still offer the course I am referring too). It would loan you some local credibility and offer you the chance to make some contacts.
Best of luck.