Perhaps you are looking at it too hard and there is a simpler way .
It depends on what you want to create .
Do you want it to be for your own personal enjoyment ?
Share with friends ?
Post on the internet and wider ?
Do you want your character to be living in the events or do you want to be a spectator ?
Do you want to create your own branch story?
What I mean is that if you wan to share it on the net and want to make it credible (like you were that guy that went to Argus and saved the world) than you need research . On the other side if you do it for enjoyment , or just you were along side that guy who saved the world , than you can have much more creative freedom .
In fact you can just spin your own story and just base it off warcraft universe .
Meaning : " Your protag lived there during that time , and things happened to him/her specifically ." No one knows if murloc 109993019 was actually capable of granting wishes , or spoke 10 languages , but your character does cause he was the one that met the murloc during his time swimming to the bottom of the zangaran swamps .
Think of how Japanese animes create filler episodes . Most of the time something happens like " they never met again , or because of magic they all forgot about it " . It lets you create pretty much anything .
You can just take an era you feel you like and spin your story for your own joy . Don’t stress too much if it is cannon or not .
You re not writing for blizzard , and even their authors just “retcon” stuff .
Here a guy who did something like this :