Ok so just think about it: Qui Gon was working for the Sith- yes i have reasons!!
Plus i have more evidence than Rey being a Kenobi.
1.) Obi Wan says to Qui Gon you would be on the council if you weren't so defiant. Just keep that in mind.
2.) Qui Gon is like die-hard to get Anakin trained. Why? Because he is working for Palpatine to find the 'chosen one' so when he did, Qui Gon will do whatever it takes to get him trained to fulfill Palpatine's plan.
3.) 'But he died' yep, ever hear dying for the cause? His death made Obi Wan want to fulfill his wish to train Anakin. He was a martyr. Now I'm not necessarily saying he meant to die, but his death only furthered their cause to get Anakin trained.
4.) I don't think Darth Maul knew about Qui Gon. Which is why he attacked and they fought each other. Palpatine was probably like ok I'm gonna get an apprentice so that you guys (obi and qui gon) can fight him and make everything seem real. Remember, Palpatine wanted to expose themselves to the Jedi. So he needed someone else because Qui Gon couldn't give up his cover. He was needed on the inside.
5.)why the theatrics? Palpatine is a politician. Enough said.
----but how did Qui Gon join Palpatine?
6.)Count Dooku. In Attack of the Clones, Dooku talks to Obi wan and says I wish Qui Gon was here right now I could have used his help. Obi says he would never join you. Thats an odd thing to say. Anyway, Dooku then says DON'T BE TOO SURE. He basically tells Obi Wan right there.
7.) We all know Dooku is in 'bed' so to speak with Darth Sidous (Palpatine). So yeah there's the connection between Qui Gon and Palpatine.
8.) 'But wouldn't the council sense it?' Ummm did the council sense Palpatine? No. (well yes but it was too late by then). And remember QuiGon wasn't on the council. So maybe they didn't sense him for that reason.
Ok there, that's my theory.