Hello! New to all types of fowl (specifically ducks)!

Hi there, I am a complete beginner to all types of... well, animals outside of cats.

I'm considering purchasing some Pekin ducks for my grandfather, who lives on a large property in the country. He is getting older, but still needs the responsibility of caring for something, or else he will get bored fast (especially since he's lost his license). Pekins seem to be like an ideal animal. I think our property is more than enough for them, and they can lay eggs, so that's easy protein that he desperately needs.

My basic questions are as follows:

1) Is there a minimum amount of ducks you would recommend? I was thinking of two females, so they have company, and there is no risk of having fertilized eggs. I hope. (sometimes life uh.... finds a way)

2) Our property is on a hill, with the house at the top. On either side are our neighbours (separated by STEEP hills), to the back is our driveway, and to the front is a beach. I am worried about the ducks running away and being eaten by bears or lunatic raccoons. Is there a way to prevent this? My plan is to turn a large area into a fenced in habitat for them, and I do mean LARGE. But I still want them to be able to roam around and discover new things. Would leashes work????

3) As I mentioned in the last question, we are on a bay off of a river. It's actually half marsh (!!!) and half beach. It's also very shallow. Would this be a good place to let the ducks explore? I would keep a CLOSE eye on them, and maybe keep them on a long leash (again, is that okay?), but the water is fresh and moving. Also, would that be enough for them, or should there still be a pool in their habitat?

4) We live in Ontario, and I'm looking around for ducklings. Does anyone have a recommendation for somewhere that sells sexed ducklings? Can I trust Kijiji?

5) Finally, in the winter, I know that given shelter and a bit of heating (and actual liquid water) they should be fine, but this is mostly a summer home (summer for gramps is from April to November). Is there such a thing as duck boarding? I'm trying to find a way to keep them in my home, or maybe a friend's farm. Does that sound okay??? I'm in the capital region (ottawa) so there's farms close to the city, and we could visit.

That's about it! Thanks for any information you can share! I'm nervous and want to do this right!!!