Ok, following changes I made to my team:
DeoxysD: Changed move Knock Off to Night Shade
Basculin: Changed move Brine to Aqua Jet / Changed item Choice Specs to Choice Scarf
Forretress: Changed move Block (idk why I put that on tbh...) to Explosion. Changed EV set from 252HP, 4DEF, 252SPD to 252HP, 252ATK, 4DEF
Overall, I think I just investigated my team quite thoroughfully and [hopefully] made changes for the better.