Technically, you cannot change the 'title' once created but you can change the 'name'. In the workflow console, it displays title and not the name. however, you can change the name of the workflow from crxde though if needed but its not displayed on the console.

Yea... You cannot change the name once created

you can find more details of Asset Picker here [1][1] https://docs.adobe.com/docs/en/aem/6-0/author/assets/managing-assets-touch-ui/asset-picker.html

Its not, Asset Share exists in AEM 6.1 aswell [1][1] https://docs.adobe.com/docs/en/aem/6-1/administer/content/assets/assets-finder-editor.html

have you implemented I18N for your titles, if so you need to get I18N for the title. refer [1] for the same[1] https://docs.adobe.com/docs/en/aem/6-0/develop/components/i18n/i18n-dev.html

list.title should get the title of your language

for your use case, you can embed the global clientlib category and override the required classes and js in your clientlibs

purpose of 'Activation Tree' is for bulk content activation. What is your use case which making it difficult to use ?

If you already have a license for any of the previous version of AEM, then you should be getting 6.1 jar for upgrade.

yeaaa.. you will be giving permissions of User A to User B which is not right.. Instead make User B also to be part of User A group so that all the ACLs will be given.