I will note that Q's Blacksmith offers some new items. However, they are mostly irrelevant, as you should have better armor and weapons by now. So don't bother, although stocking up at B's is never bad, even if her stuff is old. As for the quests?
"A Drunkard's Best Friend"
This requires you to deliver six Birdman Livers to K's Tavern. These are commonly dropped by Tangata Manu on the third level of Naraku. Odds are, you have more than enough already - I had about a dozen. It rewards 750 Macca .
"Missing Child Search"
First head to Mikado Castle, then the Castle City, then the City Outskirts. Head from there into Kiccigiorgi Forest. There, you can simply follow the path pretty much to where you found the Black Samurai on your previous visit - you should remember this.
(If not, head east to the fork, then south. Go south along the western branch of the path and follow it a while to a north/south fork. From there, go north.)
Once you meet with Timothy there, note that Flynn can only "Run" or pass his turn in battle. While you can battle the demons (your demon allies will do it), it's not very recommended because Timothy is damaged when Flynn is... Anyways, you might want to just sidestep these enemies.
Once Timothy is returned, you'll get the Silver Necklace . I'd personally keep the Red Earring on due to the 10% HP gain, though...
"Operation: Slay the Berserker"
You need to find the Berserk and Rakshasa in Naraku. One was in the southeast corner, I recall, and another far to the north of there. They're simple enemies to beat.
You must slay eight Nues, found on the 4th Stratum in Naraku. They are weak to Gun and Force, and are easy to beat, but found randomly.
"Pluck the Buds of Rebellion"
Head to the Mikado Castle area and into the Back Alley to meet and follow, then fight a man-demon. It's another easy fight.
Anyways, I think that's it for these. Return to the previous section to continue the dungeon, if you cut off in the middle.