Horatio:

"So... I'd hate to suggest doing something that might not be... moral? But, if that creepy 'merchant' has a magical balloon up top, maybe Bavlorna's been selling the things she takes from people? I'm not sure who would buy a shadow, but nothing really seems to make sense in this place anyways. What I'm suggesting is, we climb up the side of this rickety old house, away from windows, and sneak into her balloon. We've searched everywhere we can down here, and cannot look around up there while they're having their tea. Some of us can work on this clogged drain issue, and some on investigating this merchant. Who knows, she might have magical weapons or armor amongst her wares that make it possible for us to actually beat that monster in a straight up fight... which is something I really don't think we could do as things are now. What do you all think? I know it's wrong to burgle, and certainly to steal, but we can give back whatever we take when we're done. Assuming the merchant isn't herself an accomplice to all the horrible things that've happened to us, and are happening to the peoples of this land." 

The old cottage is theoretically scalable from the outside, although one might worry about the slippery rotten wood. A fall would likely only result in a swim in the swampy lake. The second floor is mostly larger than the bottom floor, so there is also an overhang to climb under. But Ben discovered at least one spot where there is no overhang to contend with: the frog-covered balcony.

" According to my Nan they eat rude children."

Ben:

“I suppose we should at least finish exploring this level; there has got to be a drain somewhere for this pool, and it might be hidden in one of these rooms.  I see the well as the source, but it is strange we haven’t seen any drains actually within the pool,” responds Ben.  Having dropped Matilda off, he takes the spear and starts moving around in the pool, trying to dislodge anything that might be concealing/blocking a drain in the pool.

Perception:  11

Titaani stands up and makes her way over to Horatio. 

"I like your plan, it makes sense," she says with a smile, only for her cheerful expression to disappear. "But..I'd rather not be the one climbing. Falling into the water below...I..." She shivers. "I don't want to imagine it. I'm terrified of drowning." 

Ben finds drains – dozens of inch-wide slots running along the edge of the pool, under a small lip. Designed to direct the overflow, not drain the pool. How it is ever fully drained (or cleaned) is a mystery. The pool is currently quite low, well below the overflow.

Climbing the exterior above the balcony would risk a fall back onto the rickety, frog-covered porch, Ben knows, but he recalls seeing no windows directly above the porch, at least across the 25 feet or so he saw above him. (Free-climbing the rotten timbers is reasonably doable but would require an athletics check unless you have rope or climbing gear. See overhang line on map.)

There are three unopened doors leading off the pool room. 

Ben:

”Look,” says Ben, showing the others the overflow drains.  “It looks like the main approach to making this pool work is to fill it from the well up to the level of these drains, then the overflow gets directed…somewhere.  If we can unplug the source flow, it should fill to these slots and hopefully start working.”

Thinking a bit, he adds, “If there is any machinery or valves controlling the flow, I would expect them to be on this level.  Let’s check the other rooms before we climb outside.”

Ben will get out of the pool and shake the slimy water off briefly while he listens for the others’ responses, though he plans to start searching rooms on this level unless someone else has a better idea.

"Sure," Titaani sighs with a nod. "Although who knows what horrors await us beyond those doors?" She glances briefly at the open door on the left side and shivers. 

Matilda was willing to jump in the well, the water was only a little prickly......but she followed Ben to check the nearest doors.

Investigation: 17

Perception: 13

All three doors are similar – made of moldy wooden planks, many of which are swollen and warped. They are all closed, but do not appear to be obviously locked from this side, nor is there any evidence of obvious traps. 

Matilda tried the handle on the southernmost door.

The door pops open with a loud creak. A large cupboard stands alone in the dark room within. Fine scrollwork frames the cupboard’s two doors, which are bridged by a circular panel of dark wood. The panel is inlaid with a silver hourglass sigil.

Cadwallader:

Cad doesn't like the idea of climbing to the roof. Too old to be doing such foolishness, though that could as easily be said of anything he's done these past few days, so probably he'll find himself clinging to the side of a witch's house before the day is through.

Still, no reason to rush to get himself killed. "I hope that Mistress Charm might be willing to tell us something useful, rather than us having to burgle her balloon." He follows Matilda and looks into the room to detect any magical auras.

((Cad was gone before Charm called them theives, so he still thinks she may talk to him.))

Ben:

Joining her in the room, Ben says, “This looks perhaps magical.  I don’t see how it could be connected to the pool, but we should check it out.”’

lacking magical training, Ben just looks for any mundane traps or features of interest on the outside of the cupboard.

Perception:  14

Matilda moves into the room and then immediately to the left side of the door as the others check the room.

Cad sees no magical auras in the small, windowless room, although he does he some footsteps on the creaky floorboards directly above.

The cupboard appears tightly closed; Ben notices that the circular panel with the hourglass sigil looks like it rotates. There are no obvious traps or locks.

Ben:

If no one speaks up to warn him of any hidden traps, Ben moves to try and open the cupboard using the rotating panel.

Horatio:

Watching the others search but not wanting to feel useless, Horatio opens the next door down. (( the center right door on the map ))

Ben rotates the panel, which opens the cabinet.

The inside of the cupboard is divided into rows of small compartments, each one stuffed with pouches or other tiny containers.

They contain all varieties of trinkets:
Loose buttons of various shapes, colors, and materials
Stray cutlery (all from different sets)
A teacup-sized ceramic cauldron containing a scrap of paper with the word “spittlespew” written on it in Common. 
Unopened letters
Old, frayed, coiled-up belts
Pressed flowers and loose dried petals
A horseshoe
Feathers from various birds
A chipped teacup

...It's a trove of odd items.