How do you add multiple spawn events in a command in Minecraft bedrock edition
Unfortunately, you can only specify one spawn event.
From Commands/summon on the Minecraft Wiki (emphasis mine):
spawnEvent: string: basic_stringMust be either a single word (no spaces) or a quoted string.
Specifies the in-game event for the entity. Should be a spawn event (event name for entities in behavior pack).
This implies that mobs can only have one spawn event.