Let me explain my question. One of the key aspects of logical replication is, that you can define what to replicate. That wouldn't work in this way, that's why i'm asking.
One of the key aspects of "standby" is that it is ready to be a drop-in replacement for the "active" server, and today our logical replication facility is not capable of ensuring that property and won't be for v11 that I can tell. I'm not certain that said capability is even a goal at present.
IOW, why do you need a "standby" that isn't a drop-in replacement for a primary - i.e., can have a filter on what replicated data it accepts?