Lots of manufacturers stick on a cool name like Arctic Pak, add tank heaters, etc and claim it is 4 season. A 4 season trailer will have dual pane windows, extra insulation, heated basement and these trailers are heavier than the ones you listed.
Excel was one manufacturer that had a -10 degF temperature guarantee. Other true 4 season trailers are/were,
Carriage
Mobile Suites
NuWa HitchHiker
Teton
Moubtain Air
A few wanta-be units are
Cedar Creek
Landmark and Big Horn
Cardinal
Our Hitch Hiker Champagne is well built and insulated and I would not spend the winter where you plan.
Ken
Amateur Radio Operator.
2023 Cougar 22MLS, toted with a 2022, F150, 3.5L EcoBoost, Crewcab, Max Tow, FORMER Full Time RVer. Travel with a standard schnauzer and a Timneh African Gray parrot