As someone who loves reading and learning about Star Wars lore, I know exactly what kind of lightsaber combat form Fiora would use. Makashi. For those who don't know, Makashi is a lightsaber form created specifically for lightsaber dueling, and was based on balance and footwork to outmaneuver opponents. Fluidity, precision, and economy of motion were relied on, rather than strength.



The most famous user of Makashi is of course, Count Dooku.



And in lore, Fiora is known as a master duelist, and her weapon and fighting style is clearly inspired by fencing. Meaning Makashi would be the perfect form for her to learn, if she was jedi.