You can give a try by creating a hit based segment condition with classification=Home and classification ≠  Electronics or doesn't exist Electronics.

Currently 400 rows are available in workspace but this is in pipeline. This will be released in upcoming Release but there is no ETA for now.

Currently this option is available within VRS. However, you can restrict the use of Metrics/Dimensions/Calculated metrics by giving limited permission to a user account based on your business requirement. For that matter, you would need to create a Product profile within admin console as mentioned b...

This is currently working as designed. However, you can contact Client Care anytime for fetching Marketing Channel Processing logs history in details for any duration.

We have an option to use drop down filter in a panel, which will work as a segment condition as well. Refer to following link: https://docs.adobe.com/content/help/en/analytics-learn/tutorials/analysis-workspace/using-panels/using-drop-down-filters.html