小白兔: Please Help!! about G-235A form

I need to fill G-235A to prepare I-485 package. For last 5 years, I have been living and working in USA for 4 years and 7 months, 5 month in Canada as permanent resident. Before latest 5 years, I worked and lived in UK for 1 year.

1). If I use Canada address in G-235A as last 5 year residence, will this cause any problem with background check? Will FBI do the check in Canada or in China? Do I need to send any additional document to show I really lived in Canada?

2). Will it be better to use my parents Beijing address instead of Canada address? Which is faster for background check?

3). In G-235A, there is question “Applicant last address outside the United States of more than one year”. Is this different from the residence of last 5 years? What address should I put here? Canada (stay there for 5 month only, counted as last 5 years), or UK (stay here for 1 year, but before last 5 years).

Thank you so much!!