Hi there,
Courtenay from Parserr here. Just wanted to let you know. This is exactly what Parserr does We were added to Flow last week and very excited about it.
Parserr allows you to turn incoming emails into useful data to use in various other 3rd party systems.You can use to extract anything trapped in email including email body contents and attachments.
In your case, you could setup a rule on Parserr to extract the Facebook content you need for every email you receive from Facebook. In flow, you could use that data with any of the other connectors.
Let me know if you need any help. Id gladly set this up for you.