Do all merchants have replacements?
I'm aware that there are some merchants who will have successors take over their shops in the case of their death or other untimely circumstances which draw them away. Does this apply to all of them? Is there a list of these somewhere?
This particularly came up because I recently had a dragon raid Riverwood and, along with several guards and Faendel, kill Alvor.
Solution 1:
Not all merchants have replacements. Anoriath in the Whiterun market certainly does not, if you're looking for a specific counterexample.
There are a number of other merchants in Whiterun who don't appear to have "understudies," such as Arcadia, Eorlund, Elrindir, and the other market merchants.
Ysolda will take over The Bannered Mare if Hulda is killed.
I don't know of any way (other than experimentation) to determine which vendors will be replaced.
I don't believe Alvor has a replacement if he is killed. When he was killed by a dragon attack in my game, I resurrect
ed him in the console (though I haven't used him since).