1、yes, of course.  see below note.

nostr:note15sza0s4yrxzx35cn3cs5xarxd48h7tgc5eyy4x0ml98jqfrk92gswyvhc8

2、 see below note 

nostr:note186wfn3zdrds9g3k2rgqxtzxxr3azfzr3vz6aa68c52kns7wqpduspmk2hh

3、yes, two kinds of group. 

nostr:note1927pnd00l22umju9xldyjc3xsrhn28tk0rxczn50pygwaft5h8kqcex9y9