What changed
A search engine returns twenty links and lets the reader choose. An answer engine returns one paragraph and chooses for them. Everything that followed from being visible at position eight stops applying, because there is no position eight.
What carries over from SEO
More than the name suggests. A page a crawler can read, a clear statement of what you do, and mentions on sites that already get retrieved all serve both. The technical groundwork is the same groundwork.
What does not carry over
Ranking tactics aimed at a list have nothing to grip. Keyword density, position tracking and click-through optimisation are all built around a results page. An answer engine has no results page, so the metric you report on has to change too, from where you rank to whether you were named.
How to measure it
Ask the assistants the questions your buyers ask and record which ones name you. That is the scoreboard, and it is the one worth keeping.