Hi @Shashi_Mulugu ,As per documentation there is only one way to retain old look 'n' feel is to disable unified shell.We tried to overlay the classes but that is not working . ThanksHimanshu

Add the js in author clientlibrary .Ref : https://sourcedcode.com/blog/aem/adding-custom-client-library-for-aem-author-editor-touch-ui 

Not sure for config specifically , may be you can raise a support ticket with this request. ThanksHimanshu

Use query builder api to fetch all assets with tags under the folder. Ref: https://experienceleague.adobe.com/docs/experience-manager-65/assets/JCR_query_cheatsheet-v1.1.pdf?lang=en 

Check  Apache Sling Referrer Filter configurationRef: https://sourcedcode.com/blog/aem/in-aem-what-is-the-apache-sling-referrer-filter-osgi-configuration 

Hi ,Kindly refer the link https://experienceleague.adobe.com/docs/experience-manager-cloud-service/content/operations/indexing.html?lang=enfor creating custom index in AEMAACS. ThanksHimanshu

Scene7 queue is shared so make sure either you process in small batches as per your business priority or reach out to adobe support team to fine tune or allocate more resources for your program for scene7 sync. ThanksHimanshu

Add you custom workflow as post processing workflow .Refer: https://experienceleague.adobe.com/docs/experience-manager-cloud-service/content/assets/manage/asset-microservices-configure-and-use.html?lang=en#supported-file-formats ThanksHimanshu

Supported format https://experienceleague.adobe.com/docs/experience-manager-cloud-service/content/assets/file-format-support.html?lang=en 

In that case you use CUG and assign those users who need access for these 2 resources .So whenever they try to access they need to authenticate . https://experienceleague.adobe.com/docs/experience-manager-65/administering/security/cug.html?lang=en