You guys also mentioned Shyvana and Olaf in the Dev Blog- How far off are they and can you share anything about their updates?
End of year maybe? We know that we want to work on them, but we don't yet know exactly what the output should be per champion yet.
Are there any plans for Galio, Aatrox and Tryndamere? (Is Aatrox considered a Juggernaut?)
Aatrox is probably closest to a Juggernaut here, but even then, his mobility profile (free target dash, specifically) is pretty contradictory to our expectation for these guys, so working on him would probably come at costs to that or something else that players see as important to his identity. That said, Gypsylord was recently looking into giving Aatrox some love unrelated to 'juggernaut' work, so he may be ready to shed some light on that in the coming months.
Are there more Juggernauts in the works that aren't Shyvana and Olaf?
Currently, no.