Can the chaise go on either side?

Yes. The modular sections let you place the chaise on the left or right when you assemble it. You can also split the pieces into a sofa plus a separate seat.

Is the linen cover removable for washing?

The listing does not state removable, machine-washable covers. Treat the linen as spot-clean only and vacuum it regularly unless the care label says otherwise.

How firm are the foam cushions?

Foam filling gives a firmer sit than down or fiber. Expect it to soften with use, and rotate and flip the cushions to keep them even.

Does it fit through a standard doorway?

Because it ships in modular sections, each piece is smaller than the assembled sofa. Measure your door and hallway against the largest section before ordering.

Is it good for a small apartment?

It works if you have one open corner. The L shape uses floor space efficiently, but the chaise still needs clearance to walk past.

What is included in the box?

You get the modular seat and chaise sections, back and seat cushions, and the hardware needed to join them. Check the listing for the exact piece count.