In The Discipling Dilemma, Flavil Yeakley wrote that Gospels show Christ's personality types in different ways. I think the same is true with His temperament.
Probably, many portions of the Gospels show Him as sanguine, a cheerful extrovert. He is shown there as a person who likes to contact people. However, "pure" sanguine people are often not so serious. Christ was serious and very patient to people. These are characteristics of phlegmatic. However, when He drove merchandisers from the temple, He probably behaved more like choleric. When He learn about Lazarus' death, He wept. This is more typical for melancholic. So, it looks like He behaved in different situations as a person having all the four temperaments at different times.
It is impossible for an human being to have more than one personality type. However, it is possible to have more than one temperament. Some people have all the four temperaments. However, still every person has one domineering temperament. Probably, Jesus did not have just one domineering temperament in the same way as He did not have just one personality type.
In the same way as the Bible does not teach to change the personality type, it does not teach to change the temperament. Eventually, every personality type and every temperament have their own advantages and disadvantages. No one of them is better or worse.
God is not limited by just one personality type or temperament since He created people having all these personality types and temperaments. He wants people to have their different personality types and temperaments since He created them in this way.