Not going to wade through all of this or offer any comment on circumstance of which I know nothing, but just wondering: has the current house owner definitely verified that the items/gold from Mem's dead vendor are NOT sitting in the house moving crate? Because that is where they would end up for the owner of the house, NOT on the house sign. You don't get told that stuff is there either as far as I know unless you happen to look to see if anything is in your moving crate (and who does that unless they customized recently?)
From the game
vendor FAQ, which as far as I know they have not changed this portion:
<blockquote><hr>
Expiring contracts: One way to terminate a contract is to not renew it. Vendors will disappear at the end of a non-renewing contract period. If either party of the contract agreement has the "Renew on Expiration" option set to "No," then the contract will simply not renew.
Once a contract expires, the vendor will immediately vanish and its inventory and funds will be moved to a special "vendor crate" (This is more like a virtual container, rather than an actual object.). This special "vendor crate" will be displayed as a single line of text ("This Packing Crate Contains X Vendors/Barkeepers.") that will appear when the house owner hovers their mouse pointer over the house moving crate.
The tenant will be able to collect any funds remaining on the vendor, as well as any items remaining in the vendor’s inventory, by using a context-sensitive menu option on the house sign.
The items will remain in the special vendor crate for 7 days. If the tenant does not retrieve their property within that time, the items and funds that were on the vendor will be moved into the main house moving crate where they will be accessible to the owner of the house.
[/ QUOTE ]
The exception to this rule is demolition pending due to inactive account by the owner, during which the IDOC phase will just keep cycling until all contracts as well as their grace periods to reclaim goods (9 days) have expired.
The most likely time that the vendor died was when the house was traded. The new owner would have inherited the existing contracts, but everyone would have to accept new terms after existing contracts expired. If someone was not around to accept their end, the vendor would immediately bail when the old contract expired, and the 7 day grace period to reclaim by the vendor owner from the house sign menu would begin.
And yes, you can tell from the house sign when it was last traded.
-Skylark
*edit* I see Petra covered most of this already