I have several ideas for Guild Hall Furnishings and one suggested improvement. I will start with the latter, as it is something that may enhance the Hall's decoration methods.

Layering:
Chests of Drawers should be able to stack to 2 tiles high.
Small Guild Hall furnishings such as Candles should be able to be placed atop Tables and Chests of Drawers.
Snow Blocks should be able to be stacked to a maximum of three blocks high, due to the potential for making "elaborate snow forts" expressed in the item's description.

Guild Furnishing Alchemy Machine:
Separate from the Armero Hunting Lodge machine, this Furnishing Machine is a creation point for the following suggested Guild Hall Furnishings.

Individual Alchemy Machines.
The Normal, Furnishing, and Sprite Food Alchemy Machines should be available as singular items in Guild Halls, purchasable from the Birdsong Emporium.

Alchemy Room Augmentation:
The Normal, Furnishing, and Sprite Food Alchemy Machines should all fit into this room for the purpose of convenience to players.

Stone Carvings:
I'm proposing that, upon death, the semi-rare Rock Jelly drops a material. I will refer to this material as a "Rock Fragment" to avoid confusion.
Rock Fragments are obtained from randomly-encountered Rock Jellies with a droprate of one Rock Fragment per Rock Jelly; the few Rock Jellies that spawn in preset locations such as Scarlet Fortress are not affected by this.
The Furnishing Machine gives recipes for Stone Carvings that require a variety of materials in addition to a number of Rock Fragments to create a Stone Carving. For example:

>>>>>Orb Display:
Requires one Orb of Alchemy and 50 Rock Fragments, plus a crown fee. Creates a 2x2 stone pedestal upon which an animated Orb of Alchemy is placed. The Orb displayed varies depending upon which Orb type was used in creation.
This furnishing displays Orbs of Alchemy as overworld, animated models. Higher-tier Orbs are brighter and more animated than lower-tier ones.
>>>>>Fire Crystal Brazier:
Requires 50 Shining Fire Crystals, 25 Rock Fragments, and a crown fee.
Creates a 1x1 brazier that uses the same model as those found in Scarlet Fortress and Firestorm Citadel. Can be placed on Tables and Chests of Drawers like the Candle furnishing.
>>>>>Fire Crystal Lampstand:
Requires 50 Shining Fire Crystals, 30 Rock Fragments, and a crown fee.
Creates a 1x1 lampstand that uses the same model as those found in the Scarlet Fortress.
>>>>>Stone Block:
Requires 40 Rock Fragments plus a crown fee.
Creates a 1x1 stone block that uses the same model as the 3-hit Stone Blocks in dungeons.
>>>>>Gun Puppy Sculpture:
Requires 50 Stone Fragments and a crown fee.
Creates a Puppy sculpture that uses the same model as those found in Sky Islands.
>>>>>Love Puppy Fixture:
Requires one True Love Locket, 100 Stone Fragments, 50 of all 5 Shards, and a multitude of other items such as Gremlin Gizmos and Iron Gears.
Creates an active Love Puppy as a 1x1 furniture item. The Love Puppy turns to follow players and shoots hearts at them, albeit at a much slower rate than in dungeons.
>>>>>Trojan Statue:
Requires 100 Rock Fragments, 200 Dark Shards, two Eternal Orbs of Alchemy, various other materials, and a crown fee.
Creates a 3x3 Trojan Statue that uses the same model as those in The Silent Legion.

Energy Mecha Knights:
This is meant to provide a reason for activating derelict Mecha Knights, and does not apply to Mecha Knight Kit Pickups.
Derelict Mecha Knights become a more common sight in the Clockworks because of this.
Every time a derelict Mecha Knight is activated, it will leave behind a material on the floor at the location it was powered up. I will refer to this material as a "Knight Motor" to avoid confusion.
>>>>>At the Furnishing Machine, three Eternal Orbs of Alchemy, 100 Knight Motors, 25 Power Cells, and various other materials plus a crown fee are required to craft a "Repurposed Mecha Knight".
The Repurposed Mecha Knight wanders the Guild Hall, occasionally shocking itself. It is not aggressive, and will not react to players. The Mecha Knight's skin changes based upon the Guild Hall's Theme, and resets every time the Theme changes. For example, a Cooling Chamber theme will give the Mecha Knight a Cryo Knight skin.
>>>>>Deactivated Mecha Knight:
Costs one Eternal Orb of Alchemy, 30 Knight Motors, and 10 Power Cells, along with carious other materials plus a crown fee.
Uses the same skin as the Repurposed Mecha Knight, but is permanently in an inactive state.

>>>>>One last suggestion.
Inplementation of a Confetti environment as well as Sky Islands and Scarlet Fortress Themes.

Thank you for reading, if you actually read all of that.
Please let me know what you think.