The primary problem with the discussion of undeath is the Defention of undeath.
Now I believe the best defenition for undeat is:
"A being who has died and there corpse re-animated, they retain no thoughts of there original owner. They lack freedom of thought"
now this excludes Shades and Myrms.
Clearly to resurect a Shade is a much more powerful spell.
For they retain there memories, powers and freedom of thought."
the defention that we can best use on this is
"Shade: an archmage who died an there body is resurected and they retain there soul and powers and freesom of speech."
And Myrms, They are not dead. Nor techinically they do not act as if alive as the scientific defenition goes.
they are in a sort of pseudo life.
There bodies no longer function and thus slowly rot. But there bodies act as a container for there souls. There souls control the movement of there 'container' by magic and not through muscles. They are used to moving in a life like way and thus still do. a journeymans Roots only free there souls from there container.
The only question is Is this magic powerful enough to continue after its casters demise?
Of that we have No idea. or proof.