We should consider using MatchExpressionParser to parse the query argument to $geoNear when creating the document source, for validation purposes. Currently (at least on some queries), this doesn't happen in normal parsing code until deep within PipelineD::buildInnerQueryExecutorGeoNear.
The interesting plot twist is that DocumentSourceGeoNear::serialize calls MatchExpressionParser::parse when serializing for PQS or query stats. This leads to weird cases where query stats sees parsing/validation errors after a query has technically been parsed (see here for more details). 

 
Once we make this change we can re-enable jstests/core/query/json_schema/misc_validation.js 
in the query stats core passthroughs.