I don't think it would make any difference at all for a few reasons.
1.) 99.9999% of the viewing population would not know the difference anyway.
2.) 99.9999% of the viewing population does not know or even care that there are supposed to be different forms of lightsaber fighting styles.
3.) Most of the real world sword fighting techniques are created via necessity. The biggest contributing factor being Armor. Different Armors are the main reason that different swords, sword shapes and fighting techniques were brought into being to begin with.
Very little of the reasons for different sword fighting techniques exist in the star wars universe because, we are dealing with... well plasma or laser swords. Because we are dealing with weapons with no appreciable weight or blade shape differences to take into account, or much in the way of armor to deal with, which in the real world affects the type of material or blade shape, the biggest, and only practical contributors in the initial reason to develop a "style" to begin with, the only real reason to develop different lightsaber forms would be to accommodate users of more exotic type weapons, such as Mauls Double bladed lightsaber or for dual wielding.
So in short I don't think they will be taking lightsaber forms into account when making the movie. I do however think that fans will assign forms to what they see on the screen after the fact, even though the fight choreographers would have had nothing more in mind than.... will that cool cool on the big screen.