The "source of causation" is 記憶を刈るという部分. The agent ("causee") is unspecified, but it's "generic you" (one/you/people/人/人々/etc). 彷彿(と)する means "to have (something you've seen before) in mind", "to imagine (something) vividly". The sentence literally means "The memory-reaping part makes people imagine メア," or less literally, "The memory-reaping part reminds us of メア."
The "source of causation" is the user of the camera, the implied subject of the sentence. The agent is レンズ. 巡る is an intransitive verb meaning "to move around". The causative part literally means "[He] makes the lens move around".
The "source of causation" is 'ドラゴン(?)', and the agent is 翼. はためく is an intransitive verb meaning "to flap". The causative part literally means "The dragon made the wings flap". English flap works both transitively and intransitively, but はためく is only intransitive, so you'll need はためかせる.
In case you're not sure why the agent is marked either by に or を, please read this. The point is that 彷彿(と)する is transitive, but 巡る and はためく are intransitive.