Variance analysis is not relevant to target costing as it is a technique used for cost control at the production phase of the product life cycle. It is a feedback control tool by nature and target costing is feedforward.
Value analysis can be used to identify where small cost reductions can be applied to close a cost gap once production commences. Functional analysis can be used at the product design stage. It ensures that a cost gap is reached or to ensure that the product design is one which includes only features which customers want.
Activity analysis identifies and describes activities in an organisation and evaluates their impact on operations to assess where improvements can be made.