As a frontline, Viktor's Barrage will be blocked by your shield if the center of the blast is outside your shield. The missiles are just a visual effect, and the explosions actually spawn at ground level.
Zhin's counter stance will allow him to counter ANY offensive ultimate especially with the counter legendary card. It can even counter torvald's hyper beam, Every hit of Makoa's Ancient rage or any damage ultimate you can think about. Tread lightly