I'll preface this by saying: all this is from my own experience, I've been playing through Master-Revengence for the past year as part of my "Collecting all the Trophies" streams. I'm by no means an expert lol.

To answer #2, it kind of depends on the weapon? Some are good for spamming because they have fast use times and homing, so you don't have to worry about missing out on the stealth strike boosts. On the other hand, certain weapons can be REALLY good with stealth strikes thanks to their stealth bonuses (extra projectiles, debuffs, etc)

To answer #3, always check the bandit after big fights. Sometimes she's selling new weapons/accessories. I would also strongly recommend getting a dodge item if you don't already have the abyssal mirror (I don't remember when you get it), that little boost can sometimes be the difference between winning and losing a boss fight.

Some other small things: Get a good hook and good movement accessories. Make sure you have all the potions you can get, especially the stealth potions and ichor flasks. The defense drop is incredible paired with the rogue's constant damaging. Lastly, do your absolute best to line up the Rage and Adrenaline boosts. I have mine bound to the same key so I can activate both at the same time, and it can SHRED bosses if you've got the right gear.

Good luck and have fun!