While R+L = J is pretty much confirmed, it still remains a theory as far as books are concerned in absence of any explicit confirmation from the author regarding Lyanna and Rhaegar's relation (Or lack thereof).
Here's what we know:
Rhaegar outraged the whole realm by crowning the maiden daughter of Lord Rickard Stark, betrothed to Lord ...
It appears from Lord Brynden's instructions, that there is no real limit on what the greenseers can and cannot see:
"Will I see my father again?"
"Once you have mastered your gifts, you may look where you will and see what the trees have seen, be it yesterday or last year or a thousand ages past. Men live their lives trapped in an eternal ...
Bran describes this himself when he is reunited with Sansa in Season 7, essentially he can see the whole past so there is no gap in time from now to previously that he can't see. Apparently he can also see the present.
Bran: It means I can see everything. Everything that's ever happened to everyone. Everything that's happening right now. It's all pieces, ...