[SalesForce] How to display fields from other parent object on related list

You can achieve this without Apex by using Process Builder on DocuSign Status.

Filters: You would want to filter that the DocuSign Status corresponds to Sample Order as follows:

• Field - use your lookup as the field, but make sure you use the lookup (ends with __c) and not the relationship (has a right arrow).
• Operator - startsWith
• Type - Id
• Value - use the first three characters (key prefix) for any Sample Order Id. For example, if it were to Account you would use a filter value of 001.

Action: You can then set the field you want on Sample Order from the DocuSign Status.

• Action Type - Update Records
• Action Name - whatever you like
• Field Update - select the same lookup as in your filter, set type to reference, and find your field.

You can't directly add a grandchild object as a related list on an object - there has to be a direct relationship. You can certainly pursue the Visualforce route if you wish.

Alternatively, you could add a new custom lookup from the Docusign status object to Opportunity, and then use Process Builder or a trigger to populate that lookup with the parent Opportunity's ID. This would create a direct relationship which would allow you to include the related list as usual.