Totally confused trying to buy travel trailer

4 season or close to that first. Most what are called 4 season trailers are far larger and heavier than you are looking at. The only exception might be Arctic Fox. The rest of the wants inside are probably not going to happen unless you strip a lot of stuff out and start from scratch. Most of the "camping" size trailers are going to have a small kitchen area, a booth dinette, a couch that makes into your bed, and a cramped bathroom and very small closet. In other words they are not really designed for a full timer, but a small family for a weekend and occasional week. Tank capacities are also going to be on the small side, limiting your boon docking ability.
You might consider moving up to around a 25 foot TT. At least then you will have a fighting chance of getting most of your wants.