If I understand the sequence.
Fuel tank - Secondary filter - new electric pump - Engine pump - Engine filter (primary) - fuel lines to high-pressure pump.
Between the tank and the engine, the fuel lines are standard hoses rated for diesel fuel. You can make them fancy, but there is no need. Basic black hoses are normal. The fuel in the hoses before the engine is at low pressure.
The fuel lines from the high-pressure pump to the injectors are different. They must be able to handle the pressures of the high-pressure pump, and usually are solid metal