Indeed details matter in many domains and walks of life! I have always lived by the idea that the whole is made up of details that I prefer to understand as best possible to see if the whole is actually what it seems.
Yes - Anavex did not outright buy the compounds in their pipeline.
The Anavex core chemistry/IP came in-house by acquiring and being assigned patents from the original inventor Dr Alexandre Vamvakides in 2007, then building on that platform with additional patents (often co-invented with academic collaborators such as Prof. Tangui Maurice). Subsequent SEC filings and press releases show ownership or exclusive rights to the key pipeline compounds.
It is very true that Anavex did not develop the compounds and to this day what the heck this actually is...
proprietary SIGMACEPTOR™ Discovery Platform that according to Anavex "produces small molecule therapeutic candidates, like ANAVEX®2-73, with novel modes of action
...remains a mystery, but most like it is a conceptual marketing ploy.