Design Tools offers multiple ways to control access to the tools to help with the roll out of the tools. 

As for controlling access to the Rich Content Editor tools (the Javascript tool tray used when editing content on a page), there are multiple mechanisms available. 1) You can install the tools at different sub-account levels thereby only giving members of that sub-account access. 2) You can pick which users should have access to the tools by standard Canvas role (admin or teacher). 3) You can create and maintain a user "whitelist" based on Canvas user ID and add users to the list as necessary. 4) There is also a setting that will "hide" the launch tools button, though the users can still launch the tools if they know the keyboard shortcut ("alt+shift+D"). We have a number of schools that are using #4 and simply hiding the button and teaching users the keyboard shortcut when they're ready to start using the tools.

As for the LTI tools, the Multi-Tool is hidden by default as an option that needs to be activated in each course navigation where it is to be used, so it's not likely that users who don't know what the tool is used for would activate it in their course. Though to be sure, when Design Tools is configured using the settings above, the left navigation button is stripped out by a little javascript even if the tool were made available in the left hand navigation of a course. 

Once installed, the Upload/Embed Image LTI tool is always available as a content editor LTI tool in the Canvas Rich Content Editor since it's a generally useful tool and doesn't require much training to effectively use.