My guy Shall I introduce you to the following characters that ALL have the surname “Whisperwind” and none of them have been stated to be related to each other.
Tyrande Whisperwind (https://warcraft.wiki.gg/wiki/Tyrande_Whisperwind)
Orenthil Whisperwind (https://warcraft.wiki.gg/wiki/Orenthil_Whisperwind)
Kariel Whiserpwind (https://warcraft.wiki.gg/wiki/Kariel_Whisperwind) [She was removed from the game in patch 9.1 due to been connected with a certain former Dev with the first name Alex. Like a lot of his OC’s in the game]
Kamatari Whisperwind (https://warcraft.wiki.gg/wiki/Kamatari_Whisperwind)
Drelanim Whisperwind (https://warcraft.wiki.gg/wiki/Drelanim_Whisperwind)
There is also Mave Whisperwind, who was a random Priestress of the Moon in Warcraft 3: Reign of Chaos for custom games. Like how Drelanim was for Wardens prior to WoD. Which made her officially canon along with some other Wardens.
When it comes to Tyrande, the only people we know she is related to in some shape or form are
Malfurion Stormrage (Husband)
Illidan Stormrage (Brother in Law)
Shandris Feathermoon (Adopted Daughter)