Hi,
1) No, I created a list in Excel with items, qty, estimated value and at the end a total value. One list for accompanying and one for items to follow. They took copies of each and stamped them.
2) my POF were US accounts (savings and 401k, mostly savings). No issues with that, but I had a printed summary with conversions to CAD, although I never used it.
3) yes, i was able to use my US cards for everything. Online ordering, uber, etc. I still use them.
4) it did, I had a line with Verizon that had unlimited US and Canada calls, text, data. No issues there. The only limitation was how much data you had daily at full speed, but we had wifi, so that was not an issue.