First bike build, help!

I'm going to be moving to a new city and have decided that investing in an electric bike would be a wise decision. This will be my first motorized bike so I'll likely go with a electric hub motor because of simplicity in installation. Its going to be my year round commuter bike so I need it to operate well in winter conditions! The trip itself is about 3.5km each way. From what I've read it appears front wheel hubs are the better option in the winter, is this correct? I weigh approximately 280lbs, I do intend to lose some of that weight but I'm not sure how much this affects parts consideration. The legal speed limit is 32Km/H so I don't need anything super powerful.

So for parts this is what I've been eying for the hub. http://www.goldenmotor.ca/products/...-Kit-with-Internal-Built%2din-Controller.html . I intend to use the 48v 400W motor. What kind of speed should I expect from this? I've also been considering a 36v 500W but I figured the 48v 400W would be a better fit.

In regards to batteries I was looking at this one, its 48v 10ah. https://www.espow.com/48v-12ah-18650-lithium-ion-battery-for-electric-bike-silver-fish-style.html .

Lastely in terms of a bike/frame I don't have one, is it realistic to expect to find a cheap one on kijiji that won't be terrible? Anything I should avoid or keep an eye out for?

Any opinions or thoughts would be greatly appreciated!

Any thoughts on these two bikes? I think this one might be a good fit? http://www.kijiji.ca/v-mountain-bik...ke/1022855826?enableSearchNavigationFlag=true

Also found this, but I don't know if it would be any good at higher speeds?
http://www.kijiji.ca/v-other-bike/g...er/1022686237?enableSearchNavigationFlag=true

Only thing I could really find by Barley was his thread about winter tires, which while full of information I think I've already decided I'm likely going to try having at least my front tire be a Nokian Mount & Ground W160. Read some good reviews on them including driving on paved roads.