Helping OP filling out a ruined dwarf city

OP wanted help for designing a ruined dwarf city, so I adapted a couple things from my setting. Since he liked it, I thought I would share it here, with a few extra bits.

-Statues which double as crypts for mummified dwarfs. Each had a secret code which animated them as golem powered by the will of the ancestors. Perhaps there is a statue for each clan, and the clan's patriarch/matriarch alone knows the code.

-A small trebuchet whose counterweight is a bronze bell. Its name is "Bing-Bang" and its ringing marks the passage of time.

-A whole network of gas lamps connected by copper pipes to a gas pocket, supplying light. It might be damaged and leaking in some areas.

-Digging is hard, and space is always at a premium. This suits dwarfs as they are more communal than most, but even a dwarf can require privacy and be a time away from others. So they there are private chambers which one can rent for a day, gain a time on them as a reward, or even as a way to keep a healthy mind. Just empty rooms with a strong lock. You bring candles, blankets, writing material or whatever you need for what you want to do by yourself. Outsiders might joke about it being a motel, and that is one of the reasons to use it, but not the main one.

-Imagine a geode, big enough to house a castle. Now imagine the dwarfs have been cultivating the crystals inside by a combination of alchemy, geomancy and bonsai-like pruning, making a mineral garden. It is beautiful even for elven eyes, and very relaxing. A few hollow crystals can house oil lamps, and the sheer refraction and diffusion makes rainbows look like amateur work.

-Dwarf defenses, besides picking stuff from castles, can benefit from trench warfare and WWI sapping. The zig-zag design to prevent grenades and machine gun fire helps against ranged enemies, and makes every corner a choke point. Dead ends, hidden tunnels, copper panels and water cups to notice enemy sappers digging...

-A library of biographies and oaths. The more oaths a dwarf has, the greater his or her social standing, as long as the oaths are kept. Those which were able to comply with dozens or hundreds of oaths are recorded as exemplary people in dwarf history. There is a section full of records which were carefully erased so no one would ever read or remember them. These were the oath-breakers.

-A chamber of bones. Dwarfs sometimes find bones of all shapes and sizes, having no idea from which creature they came. They keep them here, as a sort of curiosity mostly visited by scholars and hunters. Many incomplete and sometimes incorrect attempts to join the bones in skeletons as well.

-The underlake could have docks with a few concrete ships. Having no wood to work with, dwarfs figure out how to cast concrete hulls, sorta like what the Allies did in WW2. Probably includes external copper sheeting to preserve them.

-There are a lot of grooves and runes carved into the walls and floors in the public areas. That is a system so one can use his hands and feet in the dark and know where one is or must go.

-Certain real-life mines with difficulties to acquire wood kept columns of stone to brace tunnels and chambers, even if they contained valuable ore and gems. It was very forbidden to extract anything from them, because cave-in. This could make for beautiful sights and temptations for greedy adventurers. Digging out a half dozen rough rubies might make the whole chamber collapse.

-I didn't add this in the thread because OP didn't mention firearms, but I forgot guano is an awesome fertilizer. Imagine a series of chambers partially filled with water, heated by geothermal sources. Reserve them for bat nests. As they poop, the guano falls into the water and it naturally separates and crystalizes the nitrate. A group of dwarfs, perhaps a specific clan, paddles along the chambers, as softly and quietly as possible, gathering them with some sort of hand net. The ocasional drowned and cooked bat has its wings cut off and put to dry. Afterwards it is powdered s used as a spice. If you're curious, dried and powdered bat wings are described as "rancid but pleasant", sorta like strong cheeses.

-Another thing I forgot to include were dwarfs sharing their underground spaces with a hive of giant ants or termites. They must have a proper diet so they smell friendly to the bugs. Besides being good beasts of burden and natural diggers, they may tend to fungi farms, provide eggs, and help in defense* and scouting. The clay they make could be used for great pottery and heat-refractive bricks, based on the furnaces made with termite clay used in Africa to produce carbon steel 2000 years ago.

*Besides the popular fuck-you mandibles, real life ants and termites have stingers which inject formic acid, shield-shaped heads that block tunnels and could be trained to form shield walls, glue spit and there's a species which explodes itself to cover enemies in adhesive guts.