Escaping Tyra is very difficult, since she can reveal you easily and spray you down. Always have your impaler arrow ready and force her in front of walls. Once she's pinned, she has no ability to escape your rain of arrows (planted).
Using a shock pulse focused loadout, Grohk can frequently slow down and damage groups and even hurt fragile champions behind cover. Use hard shields (Barik, Fernando, Makoa) frequently to protect your team.
If Evie uses her Ice Block to heal herself or to avoid damage, you can scatter Sticky Bombs around the Ice Block so you can hopefully kill her. Good reaction time is the key!