I repeat one of my comments posted on Youtube
If I had my say on the way Suleiman's children were portrayed, because like a lot of people, I didn't like the way it was written in Magnificent Century, that's what I would do. ( In my eyes, Mustafa was seen as a pure white sehzade, which therefore made him in my eyes more stupid and less interesting than he actually was. Mehmed was practically erased of his personality and seen as a pure Gary Stu like his half brother. Cihangir, who I adore, yet in the series was too naive. Selim is seen as evil, etc...)
I would respect the historical point of view more. I propose an alternative version, I would have added Suleiman's children he had when he was sehzade with his other concubines before he became Sultan and met Hurrem and then had them die of the plague as it was historically.
Sehzade Mustafa - I would keep his childlike personality, except he is not close to his siblings (because of the fratricidal law), and I wouldn't put him close to Ibrahim at least until he becomes an adult and allies himself with him. I would let his mother take care exclusively of his education. A young man who craves recognition and attention from his father, who often neglects him in return over his other children due to the fact that Mahidevran is the Sultan's least beloved concubine. The more he becomes an adult, and especially a father, the more he resents his father because of the way he treats his mother and him. He does not really understand his father and therefore his fears due to the fact that he did not grow up close to him. I would keep his efficient heir personality because he performs very well despite his father never teaching him well because of his mother who is a very good advisor. Instead of doing something for his military glory or showing off his harem too much, I would focus on how he improves the lives of common people exhausted by too much conquest. I would make his guilt very ambiguous, at the start it is clear that he wants to wait for his father to die to have the throne and restore his mother's honor, however, he realizes that his father lets his vizier lead his life impossible to see even encourages him, does not hide that he preferred to have a son of Hurrem on the throne no matter what Mustafa will do. Following this, the sehzade wants to have a second plan like his grandfather in case Suleiman wants to abdicate in favor of another of his sons which would put him in danger (which could explain the Venetian correspondence, others say that it was a plan to prevent his brothers from escaping if one day he became Sultan) but hesitates to actually carry it out, then after some hesitation goes to his father's tent and gets strangled. Instead of doing Atmaca, I would focus on Mustafa's son-in-law, Nergissah's husband who started as Rustem's ally and becomes his most loyal supporter ( it seems that it is more a legend than truth, but I didn't remeber well as I didn't have on me my books of historian like Halil Inalcık) . So I would avoid making a treacherous Sehzade, his mistakes would be understandable, but he wouldn't be a pure white Sehzade.
Sehzade Mehmed: it's more complicated for him because he died without having proven himself in a complicated province like Amasya, so it's quite difficult to make a comparison with Mustafa. But I would make sure to give him a real personality: initially close to some of his brothers like Selim and Bayezid, he becomes, despite his mother, more distant towards them because of the fratricide (Mehmed II had therefore legalized it there is not much way to escape from it at the time unlike MCK) although he is very close to Cihangir and his sister. Unlike Mustafa, his father trained him in the regency of the palace and he did very well by dint of advice and practice. When he is sent to the provinces, he often listens to his mother's advice when she visits him. Knowing that he has the support of the statesmen against Mustafa he realizes knowing his father better than his half brother that he will have to play the role of the obedient sehzade not interested in politics although deep down he prepare for it. He has the happiness of being a father but dies immediately afterwards.
Mihrimah Sultan- I would make sure to respect the historical Hurrem who wants her daughter to have a marriage of love and happiness. However Suleiman prefers Rustem, and she accepts him immediately because she will do everything to save her brothers and convince her mother to accept this marriage. I would rather show her as a politician as well as her diplomatic relations. However, I would underline the unjust side of Suleiman, he had Mustafa executed and condemned Mahidevran to poverty but refuses to punish Mihrimah by banishing her because she would have helped Bayezid financially during his rebellion. Their relationship would be cold for a time before reconciling. She will be reconciled with her brother Selim because basically they only remain and will be an ally of Nurbanu.
Sehzade Abdullah- I would have included him even if he died very young.
Sehzade Selim- Initially a cultured young man very focused on charity work like his mother and sister and very sober. Nevertheless it is often sad due to the law of fratricide. When Mustafa dies, he realizes he has a chance to escape it and he will fight in a wicked way especially for his son Murad because he knows that Bayezid's temper will put him in danger besides fratricide. He knew how to recruit powerful and efficient state members. He is on the whole an obedient sehzade but who is disgusted with his father's treatment of Mahidevran (after all she is no longer a threat to him she no longer has a son) and who will take risks to her by helping her financially. As the hardships go on, his depression increases he drinks more and more especially after his sister takes the part of Bayezid, that his brother Bayezid dies, and the fact that he is obliged to make other sons in the case where Murad dies without an heir which means that he knows that his other sons will be condemned to death. He has become a broken leader although he makes sure there is effective governance.
As a Sultan he must face his father's mistakes, including the way he led the Empire, including too many wars and unnecessary conquests in Europe.
Sehzade Bayezid- Him complicated. Due to his explosive temper he is the black sheep of his siblings (Mustafa does not count since he is a half brother, they do not even know each other) and the most incompetent of Suleiman's sons and Suleiman is worried because he has inherited the worst faults of Selim Yavuz like being angry easily (without having had his qualities). Yet deep down he wants affection and that's why he has several children even if it's irresponsible, his mother favors him because she's afraid for him because he has too impulsive nature . Mihrimah comes to his aid only in memory of his mother, because deep down she prefers Selim, Bayezid knows this, which means that he hardly listens to her. She only helps him financially as a last resort because she couldn't convince him to call off the rebellion. Suleiman was more lenient to his mistakes that Mustafa (we could once again underline the unfair side of Suleiman again with this) until the point that he took refuge to the Shah.
Sehzade Cihangir- A cultured young man very close to his parents and very sick. I would make him a supporter of Selim because although he is close to him, he also knows that he is his only chance of survival because he is not close to Bayezid at all. He often sends information from the Palace to Selim to better aid him in managing his province and at times advises him to be more ruthless in his quest for the throne while remaining an obedient sehzade. It would therefore be a good adviser for Selim (and it would give him more personality). He cannot therefore be limited to the role of a simple supporter but also of a valuable advisor.
And that's how I would portray them if I were in the place of the screenwriters. They are all very nuanced (we avoid all white or all black), we can freely pick a favorite without trying to favor another sehzade at all costs, and I try to be consistent with what we know about them and try to explain why they did mistakes or make sucess.
