To me frozen and seized are roughly interchangeable and mean, minimally, a temporary capture of control of an asset. Although maybe there's some strict legal difference I'm not aware of, I'm not sure there's much practical difference from the Russian PoV.
Confiscation would be e.g. definitively taking control and disposing of it, the proceeds going in to the general funds of the relevant country.
Confiscation would be e.g. definitively taking control and disposing of it, the proceeds going in to the general funds of the relevant country.