The Code is pretty clear on a magus' right to not be deprived of his or her magical resources, but what about his or her right to dispose of their magical resources after death or passing into Final Twilight?
I recall reading somewhere a ruling that a dead magus or the ghost of a magus does not have the rights of a living magus, but there are exceptions to this such as the reappearance of the Elder Magi in the Rhine Tribunal (which lead to proxy voting) and inheritance seems to be part of some lineages.
Similarly, apprentices IIRC are considered the property of their parens generally, but I can't recall if this is just a leftover from ArM4.
So before a magus dies, can they write a will/testament detailing the disposition of their magical resources to their filii, amici and others?
If so, does this document (presumably witnessed by a Quaesitor in good standing at least) have any weight under the Peripheral Code and how is conflict with covenant obligations resolved?
Each House may differ somewhat - Tremere and Tytalus springing to mind as potentially having quite rigid inheritance systems in some respects already.
Canon is almost completely silent on this subject, which is silly IMO. The canonic legal system of the Order seems to me designed to make for an interesting (read, contentious) play environment, not a realistic system that would actually work and that magi would accept. Playing a lawyer is boring (to most), unless there is lots of intrigue and courtroom drama.
So, you are in the realm of Robbie's mantra ("do what works for your Saga") here.
In my Saga, yes, wills, inheritance, and even probate are the normal way property passes from one magus to another. (Probate is common because it's so hard to tell whether a magus is in Final Twilight, or just a really long Twilight episode.) Of course, once a magus is Renounced, his will is void and all his property forfeit to whomever slays him.
This latter point brings up a nasty conflict-of-interest, by the way: a motive to Renounce a magus in order for one's cronies (Hoplites) to get his property. One can easily imagine kickback schemes... food for thought.
I believe that Hermetic wills are a recognised part of the Peripheral Code, except, as noted, when the Magus in question is Renounced. Absent a will, the pattern of inheritance seems to be one of primogenture, with the eldest surviving Filius of the deceased Magus inheriting everything. If no Filii survive, then his Parens has a claim. If Filii and Parens are deceased, then it goes to his Sodales (Covenant-mates). If the Magus had no Sodales, then I believe it is claimed by his House.
Since the Code of Hermes calls upon a Parens and/or Filii to hunt down a Renounced Filius or Parens (as applicable), it's not inconceivable that they would inherit that way, instead.
As a side note, from what I recall a Tremere Magus who holds the sigils of others who is Renounced or dies results in the return of all voting sigils to their "proper" owners.
The only formal form of hermetically legel 'inheritance' i remember is the spoils of war. The possesison of A legally marched Magus become the property of the marching magi. Basically Bounty hunting.