Hai, for the first problem, you have another option which right click your mouse, select open link in new tab. That is the thing that I always do. For second problem, can you hear the audio from your site which I mean while you click on listen can you listen the audio message that you send ?

To open link in new tab.

Step 1: Type about:config into address bar and hit Enter

Step 2: Accept the Risk and Continue

Step 3: Type browser.search.openintab into the search bar and look for the preference

Step 4: Click on toggle to make value set to true.

Step 5: Type browser.urlbar.openintab into search bar and look for the preference

Step 6: Click on toggle to set the value as true.

Step 7: Type browser.tabs.loadBookmarksInTabs into search bar and look for the preference

Step 8: Click on toggle to set the value as true.

Step 9: After change the value, close Firefox and restart it.

Note that you can middle-click a link with the mouse wheel to open the link in a new tab.