A good Sha Lin knows how to avoid Grumpy Bombs, and you should never try to fight him alone. If necessary, stay closer to your teammates and use Poppy Bomb as an escape. Just try not to get hit by Impaler Arrow - and watch your back.
Because Torvald can no longer drain shields your ability to specifically counter him has been significantly decreased. However, you have Nullify on your side, as well as a decent DPS - don't hesitate to fight fire with fire and get into close combat.
Recently, Maeve's Midnight was heavily nerfed - it can be countered by Resilience (at the time of making this) and go down to a minimum duration of around 2 seconds. If the option is available to you, buy Resilience - especially if you're her target.
While I generally recommend Agony in the event a Ruckus is present, if you find yourself alone against a Ruckus at full health then that small time won't be nearly enough to kill him. Just shoot him, Rend Soul, and use the stun time to get out.
Whenever you're up against a Maeve, your Fireball will be necessary as Maeve is more than able to kill you from a distance. If you're alone with a Maeve and not at low health, you can put up your shield and retreat, or burn her with the fireballs.