What is confirmed
Rusty Lake officially places the game decades before Rusty Lake: Roots and centres it on service to Aldous and William Vanderboom during their alchemical work.
What the ending suggests
Player discussions connect the ending to later identities, family relationships and the consequences of the elixir. Those connections are interpretations unless an official source states them directly. Questions about who survives, how the elixir chooses and whether characters transform should therefore be read as theory, not canon confirmation.
For the chronology rather than the final scene, use the timeline and family tree.