Questions Regarding Deleting Source Data After Transform

yes, that's right.

Note that for the 2nd continuous transform you need a timestamp field to sync on. You can use the timestamp from the daily bucket, however in this case the delay for the 2nd transform needs to be 24h + the delay of the 1st transform. If that's to slow for you, you can either configure the 1st transform with a lower interval or you add an ingest timestamp using an ingest pipeline.

See: Dec 12th, 2018: [EN][Elasticsearch] Automatically adding a timestamp to documents