Sorry we missed your question! I'll make sure it's moved to the Audiences forum.
For option #1, you are correct.
What I know is that in the first option, the created Audience that is shared, is visible in Audiences Library so I can use it to build my Target activity. However, the data are under collection process (up to 48h as far as I remember).
So simply after that collection period, the Audiences have build collection of MCIDs. So, when visitor visits the page (page supports Visitor ID), then my Target Activity immediately resolve proper Audience (thanks to the MCID) and proper Offer will be served.
When the visitor returns to the page after the MCIDs have been processed, Adobe Target should see that audience information and place them in the appropriate activity.
Now, about the Marketing Cloud Audiences option:
- Audiences created in the Marketing Cloud are usually real-time or near real-time, depending on implementation, which we'll address in #2.
- If the audience is built using raw analytics data, that data is only available after the Adobe Analytics image request has been made. It's forwarded to the Marketing Cloud and segmentation occurs in real time. In a case where mbox is at the top of the page and AppMeasurement or s_code is at the bottom, that segmentation decision will be available to Adobe Target the next time mbox is called (usually the next page)
- "Collecting Data" is a generic moniker used for all types of Audiences shared to (or created in) the Marketing Cloud that have not yet reported audience sizes. Reporting doesn't refresh very often (every morning), so it's normal for "collecting data" to persist for a few days after the audience is created or shared. If it persists for longer than that, there may be some issue in populating the Audience.
Some customers have created "composite audiences" consisting of audiences shared from Analytics and an identical Marketing Cloud audience based on raw analytics data. This way, they get the advantages of real-time segmentation as well as the historical backfill provided by the Analytics Audience. Example screenshot attached