The four proposed definitions of chasidus (ch. 1) are all just particular manifestations of the essence of chasidus, but they do not capture the essence of chasidus which is infinite.
Similarly, all good and truth that may be found in any manmade system may be found in Torah, but this is not the essence of Torah.
On the Essence of Chasidus (Chs. 2-3)