Right. I'll list down all the items in broad categories on a plain paper and may be keep blank BSF forms in case they are required. Seems fine.1) I believe so, but I never explored using BSF form, so not sure. I will let someone else take this question
2) Yes you can group items, I don’t think there is a specific rule. In my case I listed high value things separate (bikes, tvs, electronics, etc.) and all small low value items I grouped (kitchen items, books, etc) They never told me or asked anything about my list. They took them from me, a separate agent looked at them, took copies, signed or stamped (dont recall) and then gave me one of the stamped/signed docs (I believe I got the original lists backed, but stamped). Each of my lists was about a page and a half, we didn’t have a lot of belongings.
3) if the items are landing with you, then they are accompanying. Would you return to the US with everything again? You can always rent storage in Canada, not sure how many things you have. After I returned as a landed PR, I was driving a minivan full of many of the items on my GTF list. They just took another copy of my already signed/stamped list of GA/GTF. They never looked at the items when I first landed nor in my second trip. I’m not sure how it would work if you leave and return with all the same items. What I would say is that you can put extra things on the lists, even if they never make it to Canada, so I guess you can always double count.
4) no, there is no need to mention this. Your intention should be stated as permanently settling, if you leavee 2-3 weeks later and then travel to Canada in the future just have some explanation as to why you had to leave/return. I was never asked why by Canadian agents, but it never hurts to be prepared.
"I was driving a minivan" - Did you hire a rental truck? If that is so, can we hire a Uhaul in US and drop it off across the border? Also, wouldn't be a violation if we enter Canada for the first time on a self owned/rental vehicle with a US plate and without a Canadian license. I know many people do this but what if some cop pulls us over for any reason.