You need to beat all 4 Loongs indeed. And the Duskveil. In NG+ you only need to beat 3 Loongs for the stronger staff, so you can ignore Yellow.
I now made the Fuban. Its probably the best though I do miss the shock damage from the Loong staff. For this one all you need to do is beat 2 bosses out of the Fuban chapter 2, and Chapter 4 Scorpionlord and final boss. I did the latter 2 since that secret area is very easy to open (it takes only 2 boss fights in the hollows) plus I accidentally skipped the scorpion first time. Fuban staff has 25% base crit. Which is about 45% when your stats are maxed, can be further enhanced by pills and cloud step. The gourd from Scorpion is great in combination with the pilgrim set, as it makes you sip super fast on top of being super fast in general.
A problem is that I really like Rock Solid, but there is almost no reason to drop cloud step for the utility it has. You can safely charge a level 4 inside RoF, you can heal and buff, wait out super attacks etc. Its too useful. I wish RS had some sort of great buff upon using or a bigger knockdown. Perhaps it should be buffed.
Never really used Pluck of Many. Too much mana that is better spent using other spells more frequently. A really underrated one is Cloud Step. It's amazing for stepping out of dicey situations and can give you free heals and buffing time. I heard Fire Ring is also really good. Saw a strategy of a guy just using Pillar Stance in the middle of the ring against Scorpion Lord and he didn't even use one sip. Whatever damage Scorpion Lord dealt, he recovered it inside the ring. Seemed like an easy cheesy strategy. People also don't use their vessels enough. Wind Tamer is a free stun that leaves bosses open for a few seconds. At the point you're facing Scorpion Lord, you might have also unlocked Yellow Lining or Ebon Flow. Both can do 30% of his health.
The ring is extremely good. You almost can't die in it and focus charges in it as well. But, if a boss is in water its useless though it works against the final boss.
You can use pluck of many without unlocking the last orb, it saves mana. And you can equip 3 (or 4 in NG+) Thunderbane curios which can be farmed from those thunder casters in the thunderclap temple.