Séance

The delayed triggered ability that exiles the token isn’t a characteristic of the token. If an effect such as populate copies the token, the new copy won’t be exiled.

If the card copied by the token had any “when [this permanent] enters the battlefield” abilities, then the token also has those abilities and will trigger them when it’s created. Similarly, any “as [this permanent] enters the battlefield” or “[this permanent] enters the battlefield with” abilities that the token has copied will also work.