Fisher's Instinct looks great, but I'm not sure I understand the others.

How is Rest different from just standing there, not casting? Does it reset the hole without dropping buffs?
Spare Handful. Is it about letting you stock fish to use for mooching later?
Big-Game Fishing. Is it just about size records? Even for collectables I can't see this mattering in any practical setting. (incoming, legendary that requires mooching off of an "especially large specimen.")
Ambitious/Modest Lure. Does "three uses" mean you can press the button 3 times to stack the effect on a single cast, or is it over three casts with increased success rates each time?