Thanks for the feedback, everyone! I'm taking notes! :)
To a few points: we want raised beds with a side because I have hip and knee issues that mean that, while I CAN garden if I'm sitting on something, I can't be on all fours without paying for it later. Those galvanized metal ones look super great - wow, horsepoor! Seriously nice!
We're in Quebec. In our specific location, we have to assume a certain amount of rot and water damage (everything is under 2 feet of snow and at -20C November-end of April, and then in mud and rain until mid-June, and then in sunshine until September, and then back to mud and freezing... ... why do we live here again???) so metal might be a selling point in terms of longevity. Costco sells some reasonably-priced ones (about 20$ cheaper than building the same thing in wood, and delivered to your door...) but they're plastic or vinyl, which cracks in extreme cold, and I am NOT disassembling garden beds every year.
In the long run (pipe dreams, etc) I'm hoping for 6-8 regular garden beds, plus 2-3 that are small but can have cold frames on top, just for season extension. We obviously won't be growing anything in -20, but if I can get cabbage and kale and greenery for a few extra months and avoid the 25km trip to the grocery store (and associated aggravation, not to mention the RIDICULOUS price of vegetables right now, 3.50 for a bunch of kale and 4$ for a cabbage ARE YOU ALL MAD, deep breath, I'll fix this...) I'll be super happy.
Regarding the compost and chicken coops - municipal regulations don't really matter, since we're in the country (about a 20 minute drive to the nearest grocery store). The chicken coop will be next to the neighbour's sheep field, if that's any perspective... ;) We're also looking at adding sheep and goats within the next 5 years. If the municipality starts harping on about our composter, we have bigger issues...