Good morning! It may be your first rodeo, but you have discovered the truth about GIS: it stands for "Professional Troubleshooting!"
I have something for you to try: replicas hate invalid geometry. The introduction of invalid geometry will fail a replica. I suspect this is what you're experiencing. To find out...
Open an mxd, and add the parent data. Start an editing session. From your editing toolbar, click the Editor drop-down, and click Validate Features. It will likely pick up all the features in your "featureless feature classes," and tell you they're invalid. This would explain the failure; an invalid geometry introduced after the replica is created will fail the replication process.
The way I get around it: fix the invalid geometry, or recreate the replica and allow the invalid geometry to persist. In your case, the actual design is creating the invalid geometry, so you would need to either rebuild every time you synch, or switch over to geodatabase tables, and hit the forums for a solution to the search/table fail issues you described.
I hope that helps!