In Julius Caesar and in The Alchemist, what traits identify characters as protagonists, antagonists, major, or minor secondary characters?

In William Shakespeare’s Julius
Caesar and in Ben Jonson’s The Alchemist, the functions
and statuses of the different characters can be determined by a number of factors. 
Those factors include the following:

• The titles
  of the plays. The title Julius Caesar quite obviously suggests that
  Caesar will be the main character, or protagonist, of the play.  To a different degree,
  the title The Alchemist suggests that Face is the main character,
  although Face seems more a part of a trio of main characters (including Subtle and Doll
  Common) than the obviously main character himself.


• The
  attitudes and attention of the other characters. In Julius Caesar,
  most of the other characters are obsessed with Caesar to one degree or another. He is
  the chief focus of their concerns, and the fact that some of them feel the need to kill
  him ironically suggests his importance, both to the play and to the political world of
  ancient Rome. In The Alchemist, Face is the man whom most of the
  dupes want to meet. He is at the center of their attentions and their
  ambitions.


• The number of lines spoken by each character.
  Caesar has many lines in Shakespeare’s play and also some of the most important
  speeches. The same is true of Face in The Alchemist. To some
  degree, the number of lines spoken by other characters in both plays is an indication of
  the importance of those characters to the design of each
  work.


• The extent to which a character determines
  developments in the plot of the play. Caesar is the driving force in Julius
  Caesar, at least until his death. If his ambitions had not been so strong, he
  might never have been killed (and the play might never have been written in its present
  form). Other characters respond to him, rather than he to other
  characters. For this reason alone, he is the protagonist, or major character, for much
  of the play. After Caesar’s death, Marc Antony in a sense becomes the protagonist for
  many of the reasons already stated. Meanwhile, in The Alchemist,
  Face is obviously the leader of the trio of charlatans who make fools of most of the
  other characters. Subtle is also inventive in creating developments in the plot, but
  Face still edges him out in this department.


• The
  antagonists of both works are the characters who seem to be in most conflict with the
  protagonist. In Julius Caesar, the most significant antagonist, at
  least eventually, is Brutus. He is the man whom the other conspirators hope to involve
  in their conspiracy. He is the man who can pose the most effective opposition to Caesar.
  In The Alchemist, there is no really major antagonist, unless that
  role is assigned Surly, who eventually sees through the scam perpetrated by Face,
  Subtle, and Doll, and who tries to unmask it. Yet Surly is to some degree ineffective,
  and thus he is not the kind of major antagonist that Brutus is in Julius
  Caesar. The same is true, and for the same reason, of Ananias and Tribulation
  Wholesome.


• Secondary characters in the two plays include
  such figures as Doll Common, Sir Epicure Mammon, Abel Drugger, and Dapper (in
  The Alchemist) and Cassius, in particular, in Julius
  Caesar.