For the main/ kitchen floor I landed on tongue and groove vinyl planks. The vinyl will do substantially better than laminate with water/ moisture, and the tongue and groove planks are much hardier than linoleum. I'll add a transition from the planks to the carpet and the side step later.
With the temperature fluctuations in the van any material will expand and contract, which I had already seen with the prior owners flooring (adhesive backed flooring which all separated). After a bunch of research I decided to go with the tongue and groove vinyl to hold the boards together, and only pinned it down with adhesive in the center row, leaving it as a partially floating floor where it can expand in both directions. I then left a 1/4" gap around all of the edges which I trimmed with a flexible silicone sealant. This will (hopefully) allow the flooring to expand laterally rather than buckling, but time will tell.