can we reuse existing transceivers ?

The transceiver API allows changing direction and transceiver.sender.replaceTrack (or SetTrack) allows you to set the track to use which means you can decide to reuse transceivers.

Note that removeTrack justs sets the direction to inactive, it doesn’t stop the transceiver the same way that transceiver.stop() does. If a transceiver is negotiated as truly stopped, the transceiver will be removed from the set of transceivers. That means its m= sections can be recycled by new transceivers in follow-up offer/answer exchanges.

The self view is used for both the sending and receiving videos of pc1, so you have to use a little imagination that the receiving videos represents other participants in the call.