Is there any way to add another table to an existing database (source = Redshift) to database (destination = Snowflake) connection without reconfiguring the entire stream and wiping all the destination data?

wut

Today it’s not possible. See issue https://github.com/airbytehq/airbyte/issues/6912

I had a similar issue, regarding refresh source schema, so that only changes need to be synced, instead of starting full refresh for all tables from start. Is this issue being solved too/in pipeline?

Yes, this feature it’s in the current roadmap for Q2