If I am the owner of a workflow and I set the status to Testing, would it initiate only if I am the one to trigger it? Afterwards, would the other actions affect other users such as the buttons would be available to users specified in the workflow? Would the email be actually sent? Would I see the buttons because the status is testing even though I would if the status is released?

From the field-level help: • Suspended. No new instances of the workflow are created and no existing instances of the workflow are executed. If the workflow includes scheduled workflows, transitions, or actions, none of them will be executed. Select this option when you want a workflow to stop executing, but you do not want to delete the workflow. • Not Initiating. New instances of the workflow do not initiate but already running instances of the workflow will continue to run. The workflow still appears on the Workflow list page. Select this option when you do not want any new instances of the workflow initiated but you still want existing instances of the workflow to execute. • Testing. A workflow instance only initiates for the owner of the workflow. Any user who accesses the record will see the changes made by the workflow. Workflow actions execute for the user even though the user did not initiate the workflow instance. Select this option when you want to test a workflow. In testing mode, the workflow execution log appears for each state on the Workflow History subtab for any record in a workflow.. • Released. An instance of the workflow initiates for any user with access to the base record type of the workflow definition. Scheduled workflows, actions, and transitions only execute when the workflow is in released mode. If you want to continue generating workflow execution logs, enable logging on the workflow definition. Select this option when you want the workflow to run for all users. IMPORTANT Setting a workflow status to Suspended or Not Initiating prevents initiation of new records into the workflow, but does not cancel any record instances that are already in the workflow.

It sounds to me that by testing, the workflow would be triggered only if initiated by the owner. But all other actions would be visible to other users such as approve and reject buttons, auto-emails, etc.

Yep that's how I interpret that

Thank you!