With reference to this question. I am referring to the lightsaber combat forms we know of (Form I-VII, as well as other named ones). The various forms are detailed in Star Wars Insider, but I am not sure what is still canon from there, if any.
Yes, they're fully (Disney) canon.
The forms are listed in full in the new DK factbook "Star Wars: Absolutely Everything You Need to Know" and as such are fully part of the new Disney-authorised universe.
There are also references to Form III ('Soresu') in Kanan: The Last Padawan and Star Wars: Rebels, references to Form V ('Shien') in Star Wars: Rebels, Star Wars: The Clone Wars and "Star Wars in 100 Scenes" and references to Form VII ('Juyo'/'Vaapad') in the novelisations for both 'Attack of the Clones' and 'Revenge of the Sith'.