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.
In a 1v1 situation Pip will definitely fail without the proper damage to counter Talus. Use his Weightless buff (as of OB62) to use mobility against Talus, and finish him off before he has time to lock onto you again.
If you have the Focusing Lens legendary, Skye can be countered if you use a Front Line as your meat shield. That Skye has nowhere to teleport; landing all five shots on her will be more devastating than you think.