I don't think so, if Kishi coordinated with the people who made the anime, it is possible to have a filler that is significant. I KNOW that fillers are supposed to be nothing related, but just maybe this time it is different. It is just like Kishi to throw in a surprise. It's not necessary that everyone has to follow the trend that fillers don't matter.
Anyways, we won't know until they actually reveal who hachibi is in the manga...but you cannot just rule out the idea..