Its pretty easy to turn both of these off and back on.
To remove the Feedback Widget (Mx Icon and the 4 icons underneath) remove the Feedback Widget in Studio/Studio Pro from and page or templates where it is used. If you want to be able to quickly put that back in place, make a copy of any page templates that use it. Then if you decide to switch it back on, you can swap templates and you’re good to go.
For the User Switcher, look in the Security section of your Project node. There is tab called Demo Users. You can select No and the black user icon will no longer appear on your pages. Want it back? Just click Yes in the same place.
Before you delete them, you probably have a good reason, take a minute and consider their use. These are two very easy to use tools and very functional.
The top one is the user-selector. Very nice to enable easy switching between users with different roles. By default an administrator and a user, but you can add other users having other roles. This widget only appears if you have your project's security settings set to Prototype/Demo and will disappear if you set it to Production.
The second one is the Feedbackwidget which allows anyone, your PO, your customer, your testers, you, to easily register feature requests and bug reports. If you want to delete it: it can be removed by ‘Find advanced’ (Ctrl-Shift-f), Search for: “Add-on widgets”. You will find the widget. Wherever you find it, just remove it.
If you don’t want to see it in local deployment you can allways hide it with some CSS