- Yes, but keep in mind that Web Edit is not completely at parity with Tableau Desktop, at least at present (10.4). and there are a number of reasons that Desktop is currently a better authoring experience. If you do go this route, however, keep in mind you need a way to create data sources and get them online, so you'd need 1 Tableau Desktop license to do this at the bare minimum.
1)Yes, Tableau online has the ability to to create dashboards. yes it can stand alone as your sole product but with limited functionalities.
You cannot create a fully functional dashboard as you can do with the desktop like adding filters and linking parameters is difficult in online when compared to desktop.
lets say you want to create a dashboard using multiple data sources, your best bet would be tableau desktop. You can only create views of the data already available on the server but with desktop slicing and dicing the data is much more flexible.
2) Yes tableau can connect to google sheets.
Hope this helps!
Please mark answered if this answered your question else let me know if you had more questions.
You will need Tableau Desktop to create views/dashboards/stories and publish data sources. Once views/dashboards/stories are published on the server, you can edit them. Refer http://onlinehelp.tableau.com/current/online/en-us/server-desktop-web-edit-differences.htm
You can publish Google Sheets as a data source and make them available on Tableau Online.