Can't speak to living spaces since we don't do that, but you have the basic process in mind. You might rip the floor planks/panels out entirely, eliminating the smelly, pesticide- laden lumber and giving access to more metal surfaces during blasting. Or, much less ideal but possible: you can seal over the nasty flooring with epoxy then leave it or put another flooring layer on top.

Haven't heard of powder coating interiors - that would be a lot of wattage! - but maybe doable with radiant methods and insulation blankets, or putting the whole thing in a giant curing oven? Most often it's just spray-on epoxy over rust-converting primer. There are low(er)-toxicity formulations out there. For undemanding applications you can paint with household enamel over primer - wouldn't hold up on the exterior though.

Interestingly, the Cor-Ten steel many (most?) containers are made of is a weathering steel that forms a protective rust layer when left to its own devices. So you could conceivably just leave it there to develop a fine rusty patina!

All told, there isn't a single "right way," to clean up a container, but there are some best practices and trends. YouTube seems to have a wealth of folks documenting their container home builds.