Although Justin has a wrestling background, he's essentially a tank striker. Khabib's striking success comes because all his opponents are so worried about the takedown.
Khabib got rocked by Michael Johnson, who KO'd Gaejthe. Michael has fast hands and good stand up, finding more success than Conor (another fast-hands striker). I don't think Gaejthe will be able to find much success striking, but he'll try to hell and back. Khabib however won't be interested in a firefight like Tony and will probably only bang it out if he has no other options.
It really comes down to Justin's wrestling. He's no slouch on the ground, but has said that he doesn't use his wrestling because it's too energy consuming. Although I feel the smarter pick is Khabib, I've been wrong about Gaejthe too many times in his past few victories so I'm gonna lean his way on this matchup