Ok at this point you have successfully made your Dummy account a manager of your Business Google+ page. Time to link your Youtube account to your Google+ page.

Log in / sign in to the Youtube account (should be the same account as the one associated with the Dummy google profile email address). At the top right of the screen you should see something like the image below. You want to click on Settings.

At this point you might be tempted to click the Associate account with Google+ BUT YOU DO NOT WANT THIS. CLICK ADVANCED INSTEAD!

Once you open the advanced settings page you should see a screen with a very important Blue button. If you do NOT see the blue button as in the image below odds are you need to Monetize your Youtube account.

Click the blue button. You're nearly done.