This is at least partially for Nick's purpose, but also just to inform.
The noble system of the Silver Empire is essentially a modern feudal society. You might ask wtf modern, but the truth is that only China had any sort of fedual-ish government past the 1600s (even then, it was on its way), and the SE world is, in terms of technological and social advancement, roughly in the early-mid 1600s (possibly 1700s) in our reckoning. The difference is that we are outside the area of familiarity for that time; Coprova is the closest thing to a United States of America, and it is functionally similar to the early US; less centralization, individual states govern their land, widely different social norms in each state. Jahari is just an anomaly, as it is a capitalist state that has never existed on Earth and probably won't for another 50-100 years. So they are kinda beyond the social development curve. We don't know much about the elves or dwarves governance. The elves are essentially little Greek city-states while the dwarves are ruled by a singular king, but we have no mention of representation, class systems, or economics.
So let's take some things we know and extrapolate.
The SE is run by a singular ruler (Empress Sophia) and her family. The royal family is supported by noble houses that operate as nearly separate feudal kingdoms, subject to the SE's laws. Due to the sovereign family's dependency on the noble houses for order and governance, they have strong political sway. However, in a situation where there is a single sovereign (and family), it is likely she has the final say in any political proceedings (though this may estrange her from support of those opposed to her decision).
The church is a separate body, and likely has no official political power -- this is not the Roman Empire. However, the church serves as an operational arm of the government, and due to the need of church services to military units, the church has enormous power, even more so than it might have with official political sway. This is one situation where the mechanics of D&D (clerics, favored souls and divine adepts can heal) impact politics. With the extreme dependency on cleric magic, the church can leverage a lot of power. As a result, there are organizations like the Inquisition which are operational elements of the government, but are part of the church. By limiting the practice of non-Dragonwright clerics, the government ensures that the church body is the only body able to support the military, further entrenching their dominance of the valuable cleric resource. It is also possible that the church itself is a political entity. However, with characters like Rowenthal who are non-nobility but present strong influence in politics, this does not seem to be the case. If the church was a true political entity, it would likely be impossible for non-nobles to become clerics (adepts unknown, favored souls are effectively sorceror-clerics so they could come from any bloodline).
So some noble rank stuff:
The Empress is the sovereign, the highest ranked official in the government.
Below her are kings or queens. These are likely the ruling members of the founding families. It is possible that there is no "king" rank in SE, in which case they would be dukes instead.
The term prince and princess are likely used for the non-ruling royal family members.
There are several "duke" ranks, and they are basically the noble family heads. It is possible that some are not dukes and are earls instead (likely), and it is also possible, especially if there are no kings, that some are archdukes.
The head of the Halvor family (not the Baron) is likely a marquis, as is any non-duke noble bordering dwarflands, Jahari, or the lizard territories. It's possible that this rank is not used, though the title "marquis" is pretty fucking cool.
Counts or earls probably encompass most of the noble heads that are not dukes. Other families that are not as close to the rulership are likely counts, as are junior members (non-heads) of the big daddy families. Counts (or earls) typically rule over counties; they are the regional governors for their noble families.
Barons rule a barony -- a small area inside a county. The Halvor county (likely not called that) has the Nedrech barony as its center region. Barons are essentially mayors, though their land governance is a bit larger.
Those are the big governor ranks; holding one means you mean something!
Below that are the normal noble ranks. Lord (or Lady) is an administrator type or leader of nobles. It may be, in the SE world, used for any noble without a governing rank (that's up to Nick). Non-nobles are not lords.
Knight is the default noble rank; because I assume a knight in the SE world is a military thing, lords may be the non-military version of knights.