Experience fragment carries its own style (element, css, js) as they are channel agnostic and use their own structure.I am wondering, you may want to use content fragment instead.
I am trying to find more details on it but meanwhile below should clear you doubt to some extent.https://helpx.adobe.com/in/experience-manager/6-4/assets/using/medialibrary.html https://helpx.adobe.com/in/legal/product-descriptions/adobe-experience-manager-managed-services.html#WhatisAdobeExperience...
Except OOTB simple content fragment, you need to enable content fragment model if that's wht you are referring to as additional functionality. You can do it by following below steps herehttps://helpx.adobe.com/in/experience-manager/6-4/assets/using/content-fragments-models.html
That's the existing issue with code for 6.1 on community. I have seen it and fixed while refactoring it for 6.4 here https://helpx.adobe.com/experience-manager/using/twofactor64.html Would recommend to take auth handler code from here and keep everything but annotations
You should be able to directly installed sp3 but make sure to take backup of instance and clean uninstall is not supportedhttps://helpx.adobe.com/experience-manager/6-3/release-notes/sp3-release-notes.html#WhatsincludedinAEM6330
OOTB notifications are sent to the person who upload the assets.You would have customize the implementation for emails.https://helpx.adobe.com/in/experience-manager/6-3/assets/using/drm.html#Assetexpiration
Are you trying to update package details like name, description, group from external application. Make sure to provide login-token or authenticate with repositoryMore details will be helpful.