I would use Virtual Private Database rather than creating its own schema for each application
How many trigger on a table ? How many users in a database ? Such question always amaze me.
Why do you want to know ? Out of curiosity or are you planning to create thousands ? For what purpose ?
Those limits are rather easy to find if you do a small effort to read the docs.
But if you explain a little bit more what you are trying to achieve, maybe people here can advise you something better than just giving a number.