My workflow would be to lay out all my Video and Audio in 1 Timeline/Sequence... making sure that each camera is on a seperate Track and the Zoom Audio is on its own track. I would then run Pluraleyes to sync it all. From there I would make cuts, Copy/Paste whatever sections I wanted into their own Timeline/Sequence and proceed with my multicam edit.
I hope you find this helpful.
Personally, I prefer to work on sequences like you suggested, however, I keep them in separate projects. Part of that is just paranoia, but part is just keeping the size of the project manageable.
When I am ready, I would import the one "final" sequence from each project and put them all together on one timeline.
Your way is how I have edited Wedding Videos for quite a while.
It also allows for more flexibility when creating a Bluray/DVD in that the more sequences you have the more options. Short versions, vows only, image montage of the couple when young, the couple miming to their favourite music track, speeches, fun stuff, arty dreamy sequence heavily graded etc.
Options, it gives you options
I prefer my Premiere project to mimic my Recording day.
1 Wedding Day = 1 Premiere Project
Multiple Wedding Parts = Multiple Project Sequences
Various Sequences & Markers = Various Encore & Disc Chapters
I've done live-event videography for most of my career and this proves to be the workflow that works best (for me) every time. When I do a live-switch and sometimes have to go in and correct a section or edit; It's just 'Logical' & easier to manage if everything is chronological... the way it happened during the day.