if you predict something that happens in the future it is not a spoiler. simply because we dont know if it is true or not. theories don't include "new info" because it's all based on things we've already seen. i don't know how to make this any more clear.
theories are not spoilers. it's speculation based on past information from the show. sometimes they turn out be right, sometimes they don't. the only things that are considered spoilers are confirmed plot points that get out by leak or any other way.
"While I can't rule this theory out completely, I'd say that chance is extremely low. Sorry, but this theory has no support in the books whatsoever. Meera does not resemble Arya and/or Lyanna in terms of physical features. There is a vague general resemblance, but there is no explicit comparison. Also, Meera is 16 in ACOK, while Jon is 15. So they're not the same age. It's possible that either or both does not know his/her true age, but that's stretching credibility a little too far. Yes, Meera is a tomboyish girl, just like Arya, and to some extent Lyanna. But so is Asha Greyjoy. So is Brienne of Tarth. So is Obara Sand. I doubt any of them are related to the Starks and/or the Targaryens."
