The following verse from Katha Upanishad seems indicative of "Kapala Moksha".
II.iii.14-16) Yadaa sarve pramuchyante kaamaa yesya hridi shritaah,
atha martyormrito bhavatyatra Brahma samaashnute// Yadaa sarve
pratibhidyante hridayasyeha granthayah, atha martyomruto bhavati
etaavad anushaashanam// Shatamchaikaa cha hridayasya naadyastaasaam
murdhaanih srutgaikaa, tayordhvam aayannamritatvam eti vishvannaanya
When all the knots of the heart are demolished- indeed even if the
Being were still alive, then the status of ‘mrityomrita’ or
‘Jeevanmukti’is attained! When all the hundred and one nerves of the
heart pass through the ‘sushumna nadi’or the crown of the head takes
to the Uttara Marg or the Solar Path or the Path of Sun then the
actual transformation from mortality to Immortality is stated to have
The import of this verse is that when Prana Vayu, after being made to travel through the Sushumna Nadi(the middle of the 3 principle Nadis),leaves the body through the Brahmarandhra(crown of the head),then it signifies that soul has attained moksha.
As regards your second question,yes, Yogis, who have mastered the movement of Prana, can make it leave their bodies through any orifice at their will.
But i have no verses right now.