Build a custom SharePoint toolbar

i need a SharePoint Expert with front end development skills to develop a custom scenario. It should work in office 365 environment. i want to have 4 buttons Invite, members,External and activity. A) When clicked on Invite button it should pop up a window showing exact features of Share button in SharePoint . B) when clicked on Members button it should 1. List of members (both individual users and security groups) with their permissions will be listed on a popup dialog. 2. Users will be able to remove permissions by clicking (x) icon shown next to each member of the site. C) When Clicked on External button it should 1. This icon has 2 states a. Green icon – indicates the site has been already shared with external users. b. Grey icon – indicates the site is not yet shared with external users. 2. When the user clicks the icon a. Popup modal window appears b. User can type the users name or provide email address c. User can choose to provide read-only or Edit Permissions. d. Once the user clicks Invite External users, all the invited members will get an invitation via email. e. Appropriate permissions will be granted to the users automatically. D) when clicked on Activity button it should display Activities such as a. New Document uploads. b. Document Edits c. Deletion of document