That’s a bad design, and goes complety opposite of established best practices.
That’s not what S/S replication is. S/S is technically 2 separate channels of one-way replication. There is no bidirectional replication in MySQL. (bidirectional implies a single communications channel with information flowing in both directions) A write on node1 is transactionally, and globally isolated from a transaction on node2.
If you want that level of communication, you should upgrade to Percona XtraDB Cluster, or use Group Replication. Both of those use a single channel for replication/communication where transactions are coordinated across all nodes.
Even in S/S, node1(s)->node2(r) and node2(s)->node1(r). As above, it is not bidirectional; there are two separate channels.
It is not. pt-t-c works perfectly in S/S configurations. In reading this post, I see more confusion and misunderstanding about S/S replication, than using pt-t-c.
See my answers in your other post.