Goal: Populate the fields Parent_Project__c and Child Project__c on the custom object Work_Products__c after a new Work_Products__c record is created. 

Background:
A Process Builder process creates a new Project__c record, with a record type of “Parent Project” when a TaskRay__Project__c parent project record is inserted.

Then,

A Process Builder process creates a new Project__c record, with a record type of “Child Project” when a TaskRay__Project__c child project record is inserted.

Then,

A Process Builder process creates a new Work_Products__c record, with a record type of “Deliverable” when a TaskRay__Project_Task__c project task record is inserted. This is where I run into trouble.

• The Process Builder process is able to create the new Work_Products__c project deliverable record and populate all fields except for the Child_Project__c and Parent_Project__c fields, because the Child_Project__c and Parent_Project__c fields do not look-up to TaskRay__Project_Task__c.
• There are lookup fields on Work_Products__c called Get_Child_Project__c and Get_Parent_Project__c, which look-up to TaskRay__Project_Task__c and link these fields with the associated TaskRay__Project__c (child project level) and TaskRay__Project_Parent__c records via traversing relationships through TaskRay__Project_Task__c up to TaskRay__Project__c and then up to TaskRay_-project_Parent__c.
• As mentioned above, there are lookup fields on Work_Products__c called Child_Project__c and Parent_Project__c; these lookups look back up to the Project__c object, filtered for the “Child Project” and “Parent Project” record types.
  • These lookups capture the associated Child Project and Parent Project records on Project__c.
  • They look back up to Project__c because of roll-up relationships that are required for reporting.

I need a trigger that populates the Child_Project__c and Parent_Project__c lookup fields on Work_Products__c with the Child Project and Parent Project record-type records on Project__c that share their names with the associated Get_Child_Project__c and Get_Parent_Project__c record names.

Schema showing the Work_Products__c, Project__c,  TaskRay__Project_Task__c and TaskRay__Project__c objects and their relationships are attached; my attempt at the required code is below.

trigger UpdateProjects on Work_Products__c (before insert) {
    Map<String, RecordType> rtMap = new Map<String, RecordType>();

    // Build a map of record type name to record types
    for (RecordType rt : [
        select Name
        from RecordType
        where Name = 'Deliverable' or
            Name = 'Expense'
  ]) {
        rtMap.put(rt.Name, rt);
    } 

    Set<Id> parentProjectIds = new Set<Id>();
 
    // Iterate over all the work products
    for (Work_Products__c theProduct : Trigger.New) {
        // If we are dealing with a "deliverable" then put it's taskray parent Id in the set
        if (theProduct.RecordTypeId == rtMap.get('Deliverable').Id) {
            parentProjectIds.add(theProduct.Get_Parent_Project__c);  
        }
    }

    // Remove any null ids
    parentProjectIds.remove(null);
    
    Set<Id> childProjectIds = new Set<Id>();
 
    // Iterate over all the work products again
    for (Work_Products__c theProduct1 : Trigger.New) {
        // If we are dealing with a "deliverable" then put it's taskray child Id in the set
        if (theProduct1.RecordTypeId == rtMap.get('Deliverable').Id) {
            childProjectIds.add(theProduct1.Get_Child_Project__c);  
        }
    }

    // Remove any null ids
    childProjectIds.remove(null);
    
    // If we have taskray parent projects, deal with them
    if (!parentProjectIds.isEmpty()) {
        Map<Id, String> taskrayParentMap = new Map<Id, String>();
        
        // Get all the taskray parent projects we need to deal with and map their Ids to their names
        for (Taskray__Project__c trpp : [
            select Name
            from Taskray__Project__c
            where Id in :parentProjectIds
        ]) {
            taskrayParentMap.put(trpp.Id, trpp.Name);
        }
        
          // If we have taskray child projects, deal with them
    if (!childProjectIds.isEmpty()) {
        Map<Id, String> taskrayChildMap = new Map<Id, String>();
        
        // Get all the taskray child projects we need to deal with and map their Ids to their names
        for (Taskray__Project__c trpc : [
            select Name
            from Taskray__Project__c
            where Id in :childProjectIds
        ]) {
            taskrayChildMap.put(trpc.Id, trpc.Name);
        }  

        Map <String, Work_Products__c> workProductMap = new Map <String, Work_Products__c>();
        // Build a map of work product parent project names to projects for any work products that match our taskray project name and are "deliverables".
        for (Work_Products__c WorkProducts : [
            select Get_Parent_Project__r.Name
            from Work_Products__c
            where Name in :taskrayParentMap.values() and
                RecordTypeId = :rtMap.get('Deliverable').Id
        ]) {
            workProductMap.put(workProducts.Name, workProducts);
        } 
        
        Map <String, Work_Products__c> workProductMap1 = new Map <String, Work_Products__c>();
        // Build a map of work product child project names to projects for any work products that match our taskray project name and are "deliverables".
        for (Work_Products__c WorkProducts1 : [
            select Get_Child_Project__r.Name
            from Work_Products__c
            where Name in :taskraychildMap.values() and
                RecordTypeId = :rtMap.get('Deliverable').Id
        ]) {
            workProductMap1.put(workProducts1.Name, workProducts1);
        } 

        // Iterate through all the work products and do the mapping
        for (Work_Products__c theProducts : trigger.New) {
            // Bail out if we're not dealing with a "deliverable"
            if (theProducts.RecordTypeId != rtMap.get('Deliverable').Id) {
                continue;
            }

            // Bail out if we can't find the task ray parent project for that id
            if (!taskrayParentMap.containsKey(theProducts.Get_Parent_Project__c)) {
                continue;
            }
            
            // Bail out if we can't find the task ray child projects for that id
            if (!taskrayChildMap.containsKey(theProducts.Get_Child_Project__c)) {
                continue;
            }

            // Bail out if we cant find a parent project for the task ray project name
            if (!workProductMap.containsKey(taskrayParentMap.get(theProducts.Get_Parent_Project__c))) {
                continue;
            }
            
            // Bail out if we cant find a child project for the task ray project name
            if (!workProductMap1.containsKey(taskrayChildMap.get(theProducts.Get_Child_Project__c))) {
                continue;
            }

            // Set the parent project lookup
            theProducts.Parent_Projects__c = workProductMap.get(taskrayParentMap.get(theProducts.Get_Parent_Project__c)).Id;

	        // Set the child project lookup
	        theProducts.Child_Project__c = workProductMap1.get(taskrayChildMap.get(theProducts.Get_Child_Project__c)).Id;
         }
      }
   }
}

Any help would be greatly appreciated!