Fake anamorphic in post: what works, what doesn't

You cannot fake anamorphic. You can, however, fake most of what people think of when they say anamorphic: the horizontal flare, the oval bokeh, the compressed face rendering.

The horizontal flare is the easy part — a masked, coloured line with a bit of noise and a soft falloff. The bokeh is harder because it requires actual defocus, so unless you shot with a wide aperture you're stuck. The face rendering is impossible after the fact and always will be.

So don't sell it as anamorphic. Sell it as anamorphic-inspired. Nobody in the audience cares about the difference; the client, sometimes, does.