Hi partner,
We can create the same 4 fields for Opportunity, then create the mapping of relationships between Lead and Opportunity, Opportunity Line, so that when we qualify Lead and new Opportunity Lines, the values of these 4 fields will be mapped to related entity.
1. Create the same 4 fields for Opportunity.
2. Create the mapping of relationships between Lead and Opportunity, Opportunity Line.
Edit the relationship opportunity_originating_lead.

New a mapping.

Select the same type fields.

Edit the relationship product_opportunities.

New a mapping. Select the same type fields.

In this way, when we qualify Lead, the field value of Lead will be copy to the Opportunity field, and when we new an Opportunity Line, the field value of Opportunity will be copy to Opportunity Line field.