Absolutely agree with Mournafein. You really want at least 6ss with the Viks, especially if you plan to take out their Avatar. I would also consider taking Taelor instead of Misaki as she has better chance of survival. Misaki works well with Ten Thunders.
The Ronin are very adaptable with the Viks and can defend/attack as necessary, so they are a no brainer for my lists.
Von Schill seems very expensive but could be a useful objective seeker. It would just suck to lose him without doing some useful things, and it is tempting to separate him from the rest of your crew with his fast movement.
Avatar: The first action the aViks must take is a melee strike against the closest model or they suffer wounds. So bringing it out when you are near enemies (especially lots of them) is the best move. Depending on flips, you will be carving away. You could also strategically bring it out to keep enemies away from an objective. aViks has no movement, but it has lots of abilities/spells to get into fights on the board. Unless your opponent has an aMaster out as well, you can guarantee that aViks is going to make an impression.