Any Project Fi and Google Pixel 2/2 XL users here?

If I were to buy a Pixel 2 in Canada, how can I activate and use Project Fi over here and when I get to the US? How do you pay you bills? Will Project Fi accept Canadian credit cards as a method of payment? I'm assuming I'll lose my phone number if I sign up and use it for a month or two and then cancel?

Thx.