Graduate Certificates or Additional Masters as addons for Terminal Degree?
From my experience teaching and applying to teach at various colleges and universities, in academia, only academia counts.
Having a degree, such as a Masters, or PhD, or DA counts.  Generally, a grad certificate, and/or any industry certificates count for zero.  A grad certificate might count if they have a requirement for a certain number of grad hours in the field.
Most universities with PhD programs want people with PhD's to teach, at any level.  They might accept a Master's, they might not. 
A technical college might let some people in certain areas teach with a Bachelor's, or Bachelor's+15 (for example).  

Essentially, look at job postings for what and where you want to teach, and see what they are looking for.  You might find that you are already qualified, or that you need a doctorate.