Just 2 sans (oh, pun.) on some thoughts that occurred to me;
Changing up the currency seems to me like a big but not insurmountable task; I'm with Talia on not shutting it down on principle, and that to integrate Lysarian properly a change of some sort could be viable.
One key factor that needs to be discussed in context is the actual minting of the coins. We're throwing out complex designs, 10 sided mithral coins, and facial details that reflect a high level of craftsmanship; enough that the difference can be recognized between various Santharian celebrities who are not necessarily known widely province to province! And this is all done purportedly without magic. I'm going to go off on a tangent, if you'll pardon me. Minting coins coins throughout the Terran world gave rise to a variety of methods. Hammered coins were made with something called a die, which is a piece of metal that had the inverse image of the coin on it. Flat pieces of metal were placed between 2 of these, and a coin was hammered out, and then through various metalworking techniques honed down to a roughly circular shape. These dies could be used for roughly 1000 coins before breaking and needing replacement. At least until the waterwheel and Mills, this was the common method in Europe. Once milled coins arrived they could be made more perfectly rounded. In Asia, they used use Coin casts. or molds; pour heated metal into mold, let it cool, out pops your coins.
We would need to borrow/combine/define a method for minting our Santharian coins, specifically with such intricate faces. Perhaps Lysarian is responsible for changing this method from say, using Dies, to instead using a Mill (we've had waterwheels since 5,000 b.S. according to the entry?!?! that's a long time to have mechanical power sitting around with no more advanced development. It was invented around the year 0 by the Greeks/Romans. We've had it for 2100 years, the Santharians for 6500. Ummmmmm.... the humans in Santharia seem a bit slow ), or maybe Lysarian decides to have coins minted using Coin Casts. Or maybe we get a new method entirely! Maybe we can get away with saying that the method is secret to protect it from forgeries. I don't know, and I know I'm drawing a lot of comparisons to Earth and I don't want to imply that we HAVE to follow the same steps in Santharia as the Ancient Greeks through the Middle Ages did. Nevertheless, we need some type of methodology, IMHO.
On the issue of the bards, I have to agree with Talia to some extent that it seems strange to have bards/artists be cast on the coins; especially local ones. Truthfully, someone living in Thalambath will have likely never heard of a local or even provincially-known figure or hero up in Carmalad. And yet, if coins are minted in Carmalad, some will EVENTUALLY circulate to Thalambath. If I was a commoner living there, and I saw the face of some unknown lady on the back of my San, I'd throw it out as being a fake. I'm not sure that minting coins in ever-smaller subdivisions of the kingdom is the right answer, and that perhaps a "Treasury" of sorts in Santhala is the right answer. More standardized coin faces, less confusion, less local-ness. I'm all for the Goldhead and the Goldsan; everyone using such valued coins can be expected to recognize those faces. I'm even comfy with the Silverbard with Judy's lovely face. Where I struggle is with the "local celebrity" or "local duke" of some of the other coins. What about just, say, the coat of arms of the capital of the province or something, if it wasn't minted in Santhala? I'm not sure I'm dead beat tired and I'm just spitballing here, but it seems like we have a lot of face-design options.
Of course, this is all contingent on the fact that certain practicality issues, require an overhaul of Judy's entry, as I see it. Not something I ever like supporting.
It is a sticky situation, and hopefully I've successfully made it even MORE complicated!
EDIT: Something tells me this will be somewhat incoherent. I'm so tired my eyelids are barely open, I'll try and be clearer tmrrw.