A series of experiments designed to evaluate various runaway electron (RE) mitigation techniques are under development for the DIII-D tokamak. The first proposed tool for RE deconfinement is a helical coil which is designed to passively drive large non-axisymmetric fields during the plasma disruption and is currently undergoing the DIII-D internal hardware review process. The current in this coil is induced by the large disruption loop-voltage and the coil design has been evaluated using electromagnetic analysis, linear MHD modeling, relativistic drift orbit tracing, and 3D finite-element modeling. This presentation will highlight overall progress but focus on 3D electromagnetic modeling carried out in support of the design. This work implemented the Psi-Tet finite-element model which was used helped to identify the effect of eddy currents on the ability to apply a strong n=1 radial field at the plasma magnetic axis. A second technique for RE mitigation involves a novel combination of secondary gas injection and a vertical displacement event (VDE) which enables access to a large benign MHD kinking event which allows the RE wetted area to be greatly increased which lowers the chance of damage to plasma facing components. This presentation will also highlight ongoing activities in the area of fundamental RE wave-particle interactions, where planned experiments involving the interaction of REs with driven helicon waves, electron cyclotron wave via mode conversion to the slow-X wave, and driven waves at alfvenic-range frequencies will be discussed. This work is intended to not only develop techniques for RE mitigation, which will be crucial for future large current devices such as ITER, but also to improve the understanding of various RE-related phenomena. Work supported by US DOE under DE-FC02-04ER54698.