We are using Salesforce Marketing cloud connector and want to use Multi org configuration. So tracking data will get back to SalesCloud in case of any type of send(initiated in SalesCloud and Marketing cloud)?
We have tried a POC with multi org configuration in one of the accounts and the tracking data seems to be updated properly. As like normal salesforce send, tracking data is updated as long as send in Marketing cloud is performed against lead id/contact id as subscriber key.
However there are a lot of other issues in the connectivity as the Multi org concept is still a beta version and i would personally recommend you to test all the scenarios before going ahead.