Do rear plugs, connectors and cable bends need to be included when checking equipment depth?

Very much so.

The chassis depth tells you where the equipment finishes. It doesn’t tell you where the installation finishes.

An IEC plug, RJ45 connector, fibre lead or other rear connection can require significant additional space, and cables need a sensible bend rather than being folded immediately against the rear panel.

This is one reason the recommended equipment depth is deliberately smaller than the available internal depth. A switch that fits perfectly until somebody attempts to connect electricity to it has only passed the first half of the examination.