Are "switching circuit" and "circuit switching" related?
&quot;Switching circuit&quot; is a concept opposed to logic circuits.

No.
&quot;Switching circuit theory&quot; is in the end nothing but a term for &quot;binary logic circuit theory&quot;. It's a term from the beginning of the computer era, and although rarely used today, describes basically any logic circuit you'll find today – from simple AND gates to a complete computer including CPU, RAM, GPU ...

&quot;Circuit switching&quot; is a concept opposed to packet switching.

Yeah, that's kind of true – when we say &quot;circuit switching&quot;, we mean that a dedicated connection for the duration of communication is made between two parties. Packet switching implies that for every data packet, the routing decision is made more or less independently of a &quot;connection&quot;.

Are &quot;switching circuit&quot; and &quot;circuit switching&quot; related?

Made of the same word. Other than that, no.
For example, the classical circuit switching is rooms full of operators taking a cable to connect two telephone lines, so that people could talk. (telephony before 1950)
That has nothing to do with what switching circuit theory is about (i.e. logic statements to be made by analyzing a circuit).

Are &quot;logic circuit&quot; and &quot;packet switching&quot; related?

You'll need a logic circuit (for example, a network card and a CPU) to do packet switching.
Other than that, no.

Is switching circuit used for digital circuits, not analog circuits?

err, basically &quot;switching circuit theory&quot; is what you'd call &quot;digital circuit theory&quot; these days.

Is switching circuit replaced by logic circuits, or does it have usages that is not replaceable by logic circuits?

This question makes no sense, see above.