How to get the nested json properties of elastic data into neo4j?

Hi, In Elasticsearch Integration
Using CALL i connect to my elastic index, then I unwind the hits as hit, and access each property as

MERGE (applicationid:ApplicationID {appid: hit._source.Application_ID})
MERGE (doc)-[:HAS_ID]->(applicationid)
MERGE (applicationdate:ApplicationDate {appdate: hit._source.Application_Date})
MERGE (doc)-[:HAS_Date]->(applicationdate)

My index has nested properties like

"Application_ID" : "004968247",
"Application_Date" : "2012-11-16T00:00:00.000Z",
"Product" : null,
"Applicant" : [
          "First_Name" : "Cameron",
          "Last_Name" : "Fisher",
          "Amount_Requested" : null,
"_original_Application_Date" : "16/11/2012"

To access the First_Name of the Applicant i tried

MERGE (applicantfirstname:ApplicantFirstName {appfname: hit._source.Applicant.First_Name})
MERGE (doc)-[:HAS_First_Name]->(applicantfirstname)

But i get error as

Neo.ClientError.Statement.TypeError: Type mismatch: expected a map but was List{Map{…………...

May i know how to access that

Also may i know how to get the properties with null like in the "Product" and "Amount_Requested", because i am getting error as

Neo.ClientError.Statement.SemanticError: Cannot merge node using null property value for amtreq


Thanks, I figured out to UNWIND the nest again and use the alias to access each properties, the null values doesn't load.