The two OmniStudio tools that should be recommended to meet these requirements are Calculation Procedure and Calculation Matrix. Calculation Procedure allows the designer to define a multi-step calculation process that can use data from various sources. Calculation Matrix allows the designer to define a table of values that can be used as inputs or outputs for calculations. In this case, a Calculation Matrix can be used to store the discount thresholds based on region and customer lifetime score, and a Calculation Procedure can be used to apply them to the orders. OmniStudio Action is not needed for this scenario, as there is no interaction involved. DataRaptor Transform is not suitable for this scenario, as it is used to transform data from one format to another.