Is it recommended that the filter is hidden at all times displaying its elements on request or have them upfront ?
Showing filters in each column is generally more intuitive.
Depending on the nature of the business of your application this can be decided. For instance, if your are looking at a financial report sort of application you may want your filters visible at all times. Probably one wants to quickly track down a transaction in a stack by just the amount or some other meta data. Most financial applications have a lot of data displayed together, so you may need it at all times.
So, as a generic answer, I would recommend this to be decided in the amount of data you are anticipating in a single screen and/ or importance to user to drill down on detail.
Hope this helps.
If your audience has not an IT way of thinkink, I will advice you to choose 3-4 useful filters for your users.
Location should be cover by the search field, and maybe some roles (if it is really useful) filter or business filter (like new users since last visit)(In my mind the email adress is not a field we use a lot for research)