MCU Zemo (and family) headcanons:
He and Heike met at university. They were both a part of the same friend group and grew close over time but they didn't start dating until after his military service.
He is multilingual, being able to converse fluently in Sokovian, English, German, French, as well as basic conversation in Czech, Hungarian, Romanian and Slovak. Russian is not one of his languages and he is bad at it.
He was a part of a fencing group at university and competed in fencing when he was in the army.
His swordsmanship skills come from weapons training when he was a boy. His family respected tradition and made him take lessons. He is also proficient in archery, firearms and martial arts but he didn't enjoy them as much.
He was considered one of the 'heartthrobs' of the royal family, and was often featured in gossip magazines in his early twenties. One magazine jokingly declared a 'day of mourning' when his engagement was announced.
He loved domesticity and being a father. If it wasn't for his commitments with the army and his team, he would have retired to become a househusband. Despite having staff, when he was at home, he cooked meals himself.
He was caught in the Novi Grad bombings of 1999 and received serious burns down his back and the right hand-side of his body. He is heavily scared and has nerve damage.
Since all the pictures of Heike and Carl got destroyed in the destruction of Sokovia, he carries around a newspaper clipping of a paparazzi shot from shortly after Carl was born.
After dropping Heike and Carl off at his father's estate, he went to join the battle of Sokovia with the rest of his unit. In the car on the way, his son made him promise he would bring Iron Man back to meet him.
Oeznik would sneak Carl a Turkish Delight from the jar every day. Zemo pretended not to notice because he remembers Oeznik doing the same for him.
Carl started idolising Iron Man after seeing him on the news (he was too young to understand the context). He used to run around pretending to shoot his parents and staff with the palms of him hands. While everyone else put their hands up in mock surrender, Oeznik would always play along by collapsing on the floor with a hand to his chest.