It does not make a difference if open in the panel or own window.Though the open will only be clicked if the user agrees to display the images of the E-Mail. This applies to both ways showing the message

I guess you are using a "Recurring Delivery". In standard configuration, this will create a monthly copy (e.g. "[2020/07] purchase follow up") for the mail sending.Thus your query does not match. Options:use the contains as you didinstead of checking the delivery, follow the master link and check th...

It indeed would make sense to be moved along with the workflow. You may raise an enhancement request on this. It's read-only on the UI but you can move the delivery using a technical workflow

yes, content block can do it but it's not officially documented so product support won't help you on any issues.

If you choose something here, it will be shown in the left-side of the query window.I.e. kind of quick access for users to use it in a query.If you don't choose anything, it's only available in "profiles (attributes)" drop down list.

You might be able to use the option "Check columns from file against column definitions".Though then also the column headers always need to match

If you want to do a loop, the official way is to use the Product Listings feature:https://docs.adobe.com/content/help/en/campaign-standard-learn/tutorials/designing-content/product-listings-in-transactional-email.html JavaScript for parsing etc. is not supported in ACS

These steps allow only for "inbound", i.e. a system sending data to campaign. For outbound it's rather the steps which he described already

Yes, these steps are correct for outbound SFTP accounts.here support will generate the key pair and provide the public key to you. It could be that you may do step 3 first (i.e. create SFTP account) and then tell support to create a key for that one but not 100% sure

The GetDate() returns current data + time.So if run today at 4 p.m., it will consider anyone who did not open between NOW and NOW-60 days (i.e. 4 p.m. on the day which is 60 days ago).So that shall satisfy your requirement