.. Getting Edgar's key

Always something to trade, isn't it. He is really enjoying his bath. But he wants it to be more relaxing.

Have you spotted some bath related products somewhere, before?

There is a bubble bath bottle in Meowy's Mporium exchange bin.

But, to get the bottle to Humboldt you need to change your clothes and leave all your items...

Through the window. Use the bottle on the hot tub, not Humboldt.

The key is there for grabs. Go change and grab the key.

Now you just need to smuggle the key out.