After finishing the From Ashes mission, there's a brief pause before Javik becomes available as a squad mate or has anything to say.
How long can I push From Ashes before I've missed opportunities to improve my Shepard's friendship with Javik? I'd like to bring Kaidan to Eden Prime, but as Kaidan becomes a squad mate fairly late in the story, I'm hesitant to wait that long before rescuing Javik.
You'll miss out on some of Javik's comments about the Tuchanka situation, but you can still become friends with Javik if you wait until after the Cerberus coup attempt to recruit him. All of his major dialogues should still be available/trigger.
The brief pause is only if you recruit Javik at the very start of the game, because the game requires that you have Liara and James on Menae when you recruit Garrus. If you recruit him after you also recruit Garrus, he's available immediately IIRC.
