Remote pinning would work as any other node that you give the permissions to read the feed. This node would follow the CRDT changes, persisting them locally.

Each keystroke produces a change in the CRDT, which is then eventually propagated to all participating nodes.

Each CRDT message is signed and encrypted before being sent over the IPFS pubsub network.

This protocol is not IPFS-specific, but there are plans to change this: https://github.com/ipfs-shipyard/peerpad/issues/107

The snapshotting occurs over IPFS, producing a static and encrypted self-contained snapshot, published over IPFS.

It is possible to access the CRDT properties inside the core library, where the CRDT is formed: https://github.com/ipfs-shipyard/peerpad-core/blob/master/sr... . This could be exposed if you would require it..