It occurred to me that I haven't really laid down what the units of currency are for the various races in Harkovast.
There are quite a few references to money, but no specifics.
Not being an economist, I am not going to go into the exchange races between all of these (that is a bit much even for me!)
I've included the pound equivalent and the pence equivalent.
Cultures that only have one unit just use very large denominations (like 100 unit coins).
Cultures that are not included either do not use formal currency, use those of neighbouring nations or I just forgot them…cause I suck.

Darsai- Coins of the Realm (called Realms) + Groats
Nymus- Drachmas + Pennies
Ivos- Denaries + Sestersies
Golta- Dollars + Cents
Zadakine- Doubloon + Ducats
Al-Saigal- Sheckles
Tendu- Rupees
Levengroust- Levenmarks + Marks
Galdrasai- Francs + Centimes
Lukov- Roubles + Kopeks
Rojun- Peseta + Centimos
Naljun- Lyra
White Kingdom- White Yuans + Fens
Eslum- Sovereigns + Coppers
Knarl Empire- Imperial Dinar

Note that some of these currencies are defunct.
How widely currencies are accepted varies greatly. The more cosmopolitan and visited by foreigners place is the more likely the businesses there are to accept foreign currency.
Zadakine cities are especially likely to accept a huge range of foreign monies.
The White Kingdom uses a single unified currency, with coins used by all its member races being identical, regardless of where they were minted.
The Knarl Empire also uses one universal currency throughout, though exact coinage is not very well regulated, so coins from one area may look very different from those in another.
The Eslum, despite being (currently) three separate nations use a unified currency. Though each nation mints its own coins they all share a uniform value.
This came about during a period known as the Reign of Suffering, when Vesladorio the Mariner attempted to unite all the Eslum under a single ruler.
Recognising the importance of economic unity, he went to great lengths to destroy all the preexisting currencies and had vasts amounts of his new new money minted.
So much of it came into circulation that even after his brutal regime was over thrown, it still remained the only functional currency. However, so hated was The Mariner that people were known to scratch Vesladorio's image off the coins before using them once he was out of power and all the coins minted after his death bore the image of the new rulers of the various Eslum nations.

Would I assume that all of the currency is in coins made of valuable metals giving the currency actual value? That would make a lot more sense for the time period.

Are the Lukov bears? Or would that be a little too predictable?

Lukov are bats.

And now you know!

Yeah, coins made of metals of the right value would make most sense.
Though they are not all solid gold like in DnD, where buying a house costs more gold then you would find in fort knox.
Damn you, fantasy hyper inflation!

Ah, I'm presuming that is THAT mariner.

Bet he's not quite as fun as Samuel Taylor Coleridge's Mariner!

Have I mentioned The Mariner before?
I might well have, because he is quite a big deal.

I just noticed I left off the Knarl Empire! Doh! Fixed it now.

with some of the nations using currencies with different denominations, it seems that some of the economies, the zadarkind for example, have gotten at least somewhat past mercantilism, and to more modern economics, where inflation in relation to other nation's currencies must be considered. do any of them use paper currency?

The understanding of economics, even by the Zadakine, is pretty weak in Harkovast.
The idea of a national debt, inflation and other things that seem pretty obvious to us now are fairly modern ideas so in Harkovast they are not really known.
I don't believe there is a culture in Harkovast that issues paper money, certianly none spring to mind.

Imagine you're a badger/cat/weasel/bird man and you're leaders suddenly say: “The gold and coins we use in daily business is to be replaced with paper representing that wealth. All gold and other metals used for financial transactions are to be claimed by the nation, and will be henceforth represented by the paper currency.”

I don't think that would go too well, even if they printed Redeemable in Gold on every note.

I think thats the kind of thing that could start a second Golta revolution!