I've gone through your concept for the ST and done a bit of theory-crafting. Before I go any futher could you tell exactly (or at least a general idea) what you use each stat (health, int, etc) for currently / what you plan to do with them? Also could you clarify "resolving known issues with items/traits systems and min/max levels of stats"?
Lot of what your talking about requires some prerequisite knowledge of your past development and only so much can be gleamed from the code.
Items/traits proposal was prolly the worst entry point into development as it deals with a lot of in depth logic. That's why I suggested Battle Engine and reaffirmed slave training as those are separate modules that don't assume you know the game right off the bat.
There is nothing wrong with items/traits. Dark wants a very complex system with loads of options and having game anticipating every single scenario. I am not confident that it's a reasonable approach. In any case, creating extra layers of stats and delimiters would make it possible but right now the only issue are two or three items and slight modifications to them will make the game run perfectly.
*Stats:
You can play the game a bit to figure it out but in general:
Health: Damage to the character. 0 - (No fixed max) Used everywhere, also a battle-stat.
Vitality: Ability to preform any tasks (inverted Fatigue), defines how tired a character is. (0 - 300). Used everywhere.
Charisma: Beauty and Persuasion ranged 0 - (No fixed max), use mostly during girlsmeets, strip job, interactions, sex jobs.
Refinement: Sort of noblemen behavior, more or less the dictionary definition of a word. (0 - no fixed max). Use for some jobs.
Libido: Extra modifier during the sex jobs. Presently not used. (0 - 100)
Constitution: Kind of strength of body. One of the most important stats in the game as Action Points depend on it. (0 - No fixed max)
Joy: Happiness of the character. Used in a lot of places (0 - 100)
Character: Will-fullness, inverted obedience, persistence of personal believes. Used in a lot of places. (0 - no fixed max)
Reputation: Not widely used. Reputation in a city, high means positive, low negative. There is no content to specify what exactly negative and positive mean in specific terms. (0 - 100)
Fame: Same as above but determines how well known character is.
Mood: Not used.
Disposition: Attitude towards main character ranged (-1000 to 1000), used in a lot of places in the game.
Intelligence: (0 - no fixed max). Means exactly what you expect.
Luck: (-50 to 50). Used in a lot of places, to improve random chances, increase rewards, increase chance of critical hits in BE and etc.
Attack/Magic/Defence/Agility/MP are all battle stats. Usually mean what you'd expect and don't have fixed max with 0 being the minimum.
Service: General stat for all service related tasks like bar-tending, waiting (being a waitress), cleaning and so on. 0 - no fixed max.
Anal/NormalSex/BlowJob/Lesbian - sex stats (0 - no fixed max)
Strip: Striptease stat, same range as the above.
Stats have two maximums called max and lvl_max, for fixed stats they are the same while for normal stats, they increase on per level basis. max is generally higher but increases slower (3 points) while level max is lower at a start but increases faster (5 points per level). Items and traits can raise normal maximum, nothing except leveling up can raise level maximum. Obviously expensive, powerful items that can raise normal maximum will be much more effective at higher level.
I hope this clears some things up a bit

PS: MC (always male at this development stage) has one sex stat to replace all sex stats. Range depends on a class chosen at game start.