The best available documentation is the source code: https://github.com/online-go/online-go.com/blob/devel/src/views/Game/AIReview.tsx. There is no public documentation for aireview api.
/termination-api/game/${game_id}/ai_review/${ai_review_id} returns a json with all available review data. Coordinates start at the top left corner as 0-0.
updateHighlightsMarksAndHeatmaps should be the function which places the marks on the board. A substitution win_rate -> score should work.
The winrate graph is at https://github.com/online-go/online-go.com/blob/devel/src/views/Game/AIReviewChart.tsx