Sounds like you're doing well so far then! :) I'd say keep that up and they should be fine! Especially since Pekins are pretty friendly and especially food oriented and not likely to want to wander far.
And wow, that's awful about the wild duck :( sorry :(
I think that it's definitely possible! However, I,wouldn't recommend just putting them out there from the start. I'd get some babies and raise them and then when they move outside keep them locked out a couple weeks so they know where home is and then you could probably start letting them out...
No problem!! I thought that was a good idea too :)
Here's the article from Metzer with a little bit more info on it!!
http://www.metzerfarms.com/RearingInstructions.cfm?CustID=9981610
Meyer has a lot of great coop plans, personally I really like the New Englander and the Gingerbread duck house :)
https://www.meyerhatchery.com/productlist.a5w?subcat=5098&cat=1027
But anyway, i think a big thing for ducks is that unlike chickens they like to be low to or on the ground and...