Is there away to make TextEdit an option under openwith for all file types

This can be done on a case-by-case basis. Select the document that you would like to have TextEdit open. Do a Get Info from the Finder menu (or command-I). You will see an option to change the application that opens the file. Change this. A dialog will ask you to confirm that you want every file of that type to open with TextEdit. Say yes. Viola.

Otherwise, I think that you cannot set TextEdit to open something that it cannot by default open.

I do not know a shortcut to make this happen across a broader range of file types.

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JJW

It would likely be easier to set up an Automator Service to open any file with TextEdit.

New Service

Service Receives Files and Folders in Finder

Filter Finder Items (Kind is not folder)

Open Finder Items (Open With: TextEdit)