How much Billie and Ronan know about Justin's past now?

[SPOILERS AHEAD] . .. . . .

On the episode 1x11 Poison's Eleven, Ronan and Billie watched a lot (but not all) of Justin's memories. I picture it was like watching a compilation of Justin on the OG series but from Justin's POV, but how much did they saw? Do they know about Julieta? The other girls? I think if they saw any Alex and Justin interactions, they would really think Alex is cool, and how much her personality is like Billie. Just wanted to yap a little about it