I am not touching the dark abyss question.
On the drawers look around at antique furniture places or places that sell those do it yourself stain it furniture and what not. Home puppet and others are good as well. One in the middle or two spaced evenly from the sides would work well. And show damage should they be opened without a key. Some are easy to pic though, so look around.
Find some brass locks that are not too hard to make a slot for. The light wood of the dressor can be drilled easily in most cases with a lock surround hiding slightly damaged edges of the hole. Something simple like a lock for a filing cabinet or whatever would most likely be fine, and in an emergency could be ripped out anyway. I would reinforce the handles for withdrawing the drawer for the brute force approach though.
I have a safe but do want something like this as I need somewhere for storing some other stuff in the bedroom, I really need a hobby room but do not have one. I think the drop bolts are good, a length of pipe drilled to take a pin or something could be added later to deter the kids climbing on it to pull the rods out.
I never have liked the glass faced gun cabinets, though I like looking at my stuff, I just like a closed cabinet. And this is close to what I want.
The metal reinforcement is a good idea, and depending what it is coat it so it can not rust and then wrap it in pool table felt. I do love that stuff so much. Make sure the legs and what not can support the weight though.
I bounce back and forth on making a metal thing like this and covering it with wood, or taking a wood one apart and reinforcing with metal. I want more than a flimsy gun cabinet, love the appearance of nice wood furniture, and know no one makes what I want.
The hooks for muzzle loaders are something I will look into, there are rubber coated metal hooks for mechanics tools and stuff, go to home puppet and look in their organizing section. You can also get a rubber liquid that is for dipping the handles of tools in for that rubber coating you often see on tools. It is liquid, you dip it in and the pull it out and let it dry. It would work for people who want to make specific heavy hooks just for their stuff. Tough rods of metal or strips can easily be bent with a little heat and a vice. Then rubber coat it for a personal apperance.
On the ammo, I would keep the guns loaded myself and make the drawers hard to get into. I am single and this is my reasoning for my situation.
Congrats on a good job, and giving me some pics to work from.