If Fernando doesn't have his shield up, try to hit him with your spit (don't detonate it). After it hits, you do more damage to him with your rockets, taking him down faster.
Encountering Grover in long range open spaces - don't PEEK around the corner.
Good Grover players throw axes preemptively and you can take a lot of damage. Use short sprints between cover. This way it's harder to predict where to aim.
Lex have more damage, but androxus wins on mobility.
Try to strafe/dash in between shots, and use your Q on his RightClick and you should win.
This is a skill match up.