I thought others said the info at your second link was considered a bit out of date. ('no one should use mq anymore' was the gist of it. but it's all I ever used) that information was moved to the wiki and trimmed quite a bit: http://wiki.octave.org/Mercurial
This is definitely something that could probably use it's one consolidated wiki page. maybe those who ran the OctConf info session on mercurial could put an outline together?