Referencing an earlier Snap

Hello.

I'm trying to pass a JSON as a pipeline parameter, and I've prefixed my pipeline with a Mapper Snap to "parse" the JSON and the output of the Mapper is a JSON object I can reference later in my pipeline. A sample of this JSON is such:

{
"extract": {
  "source": {
    "schema": "public",
    "table": "table",
    "account": "../../shared/source-dev",
    "pipeline_name": "projects/shared/query_extract",
    "load_type": {
      "full-load": {}
    },
    "target": {
      "s3_account": ",../../shared/s3",
      "target_bucket": "dev-bucket",
      "target_path": "snaplogic_test.csv"
    }
  }
}
}

And here is the Mapper (the output is "input_params"):

I've reduced my pipeline to the minimum pipeline where I still have this problem. 

I have my Mapper mentioned above, a Pipeline Execute to query against the source, a Router for doing different actions based on if there are results, and if so a Pipeline Execute to write that data to S3. I think I'm missing a few things like parsing documents into a JSON or whatever for s3, but I'll cross that bridge when I get there.

The problem I am running into is that in the router and pipeline execution, I can reference "$input_params.etc" in the expression logic, but once I am past that I can no longer reference it. 

So my questions are:

1. How can I reference that mapper output "input_params" for my s3 pipeline?
2. Is there a better way to take a single JSON parameter and make its parts available throughout the entire pipeline?