Systems and methods for neuromodulation therapy are disclosed herein. A method in accordance with embodiments of the present technology can include, for example, positioning a plurality of reference electrodes at the skin of a human patient and intravascularly positioning a plurality of ablation electrodes within a blood vessel lumen at a treatment site. The method can include obtaining impedance measurements between different combinations of the reference electrodes and the ablation electrodes and, based on the impedance measurements, identifying two or more electrode groups for treatment, where at least two of the electrode groups include a different one of the reference electrodes and a different one of the ablation electrodes.