If I remember them all, you can get into Heichu stance from 66P+K, 2H+K, 8P, and 3PP. Also the strings that contain those moves (PP2K, 9PP2K).
For the Heichu throw, you can get there from PP, 236P+K, 2K, 33P, and strings contain those moves (P2K, 4P2K).
EDIT: While we're on the topic of move...