I am confused about these possibly nonstandard sentences concerning theater acting:
Dictionaries seem to equate "role" to "character". So, are sentences 1 & 3 poorly written due to redundancies of "the role of"?
I think they are equivalent. You could say (1) is redundant but it's a common way of phrasing it nonetheless. Both sound perfectly normal and I have not been able to think of any difference in meaning.
"The role of" might be standard to say in reviews or writing about theater, but that's a guess.
(I speak American English.)
Both versions are well constructed, and both are unambiguous if the context limits the word he to an actor.
Without the context, however, the shorter sentence could be a somewhat colloquial reference to another character betraying or manipulating the main character. The first sentence does not have that ambiguity.
[Response to request in comments about the new sentences 3 and 4.]
Sentences 3 and 4 are poorly written. One normally performs an action (e.g. perform an operation), not a role. However, you could say, "He performed as the main character."
