cee'd/Ceed
All generations are designed by Kia Europe in Germany, including the derivations pro_cee'd (coupé), Proceed (shooting brake) and XCeed (crossover) and they are all built in Slovakia (or in Russia for the local market). The cars listed on the site still have origin South Korea for some the entries. To be noted that the first two generations [ED] and [JD] are badged "cee'd" and the new [CD] as "Ceed".

Rio
Global Rio models all are South Korean designs, what I'm not sure of is where the version for Russia and China were developed. They have model codes [QB] for the 2012-16 model and [FB] for the 2017+ model. They differ from the contemporary global Rio models by exterior design, some engine options and larger sizes. The most recent model originated also a crossover model similar to the Stonic, called Rio X-Line in Russia and KX Cross in China.
I suppose that these models were engineered by Dongfeng-Yueda-Kia in China, but I don't have sure informations about this

Seltos
The global Seltos [SP2], designed in South Korea, originated two versions for emerging markets:
- the Indian [SP2i], with shorter wheelbase and a slightly different exterior design, which is also exported to Africa, Latin America, Middle East and several South/Southeast Asian markets (except the Philippines) and is also assembled in Vietnam
- the Chinese [SP2c], originally badged as KX3 until April 2023, which is exteriorly almost identical to the global model, but is slightly longer.
As for other similar cases, I'm not sure how they should be handled. Maybe the [SP2i] could have Indian origin, but the [SP2c] could to be too similar to the global one to have a different origin

Venga
The Venga [YN] is an European design of Kia Europe of Germany and is built by Hyundai in Czech Republic until MY 2011, then by Kia in Slovakia. https://imcdb.opencommunity.be/forum_topic-7034-85264-Mass_change_model_info_thread.html#p85264

Pride
The original Pride [UB], as a rebadged Mazda 121, is a Japanese design commissioned by Ford, which originated also the Festiva. A reference can be found here: https://www.carsguide.com.au/car-news/mazda-121-carsguide-car-of-the-week-16571
So I believe that the Pride [UB] should have Japanese origin, and same should be for the first-gen Ford Festiva. This is valid for sure for the hatchback model, not sure about the saloon and the wagon, which weren't available for Ford and Mazda. Other variations, as like fastback or pickup models, are Iranian designs of SAIPA.

I'm not sure about the new Carens [KY], which is reserved for emerging markets, and its sister model Hyundai Stargazer (built exclusively in Indonesia), neither of the small SUV Kia Sonet, which is a derivative of the Indian version of the Hyundai Venue [QXi].

I checked the local names of the wagon variants of cee'd/Ceed and Optima models. The list is not complete because it mainly bases on brochures data, as archive.org stopped archiving Kia sites starting from 2013 (so the issue concerns the 2nd-gen cee'd and the Optima).

cee'd [ED]
It seems that the [ED] wagon is almost everywhere badged as Sporty Wagon. Most sites list it simply as cee'd_sw, but then reading the description pages the Sporty Wagon name is almost always explicited. The reference to the Sporty Wagon name is missing only in Norwegian, Polish and Russian sites (only reffered to as cee'd_sw).
In Britain it's confirmed the cee'd SW name https://autocatalogarchive.com/wp-content/uploads/2017/01/Kia-Ceed-2010-UK.pdf

cee'd [EU] or [JC]*
Mostly badged as Sportswagon (we have proofs from Austria, Germany, Iceland, Netherlands, Sweden and UK). Referred to as cee'd_sw as like the previous generation on the Polish and Russian sites, with no other badges reported (neither Sportswagon nor the previous Sporty Wagon).
Officially called cee'd SW in France by brochure https://autocatalogarchive.com/wp-content/uploads/2018/02/Kia-Ceed-2012-FR.pdf

Ceed [CD]
AL: Ceed Sportswagon
AT: Ceed Sportswagon
BE: Ceed SW
BG: Ceed SW
BH: Ceed Sportswagon
CH: Ceed Sportswagon
CZ: Ceed SW
DE: Ceed Sportswagon
DK: Ceed SW
EE: Ceed SW
ES: Ceed Tourer
FI: Ceed Sportswagon
FR: Ceed SW
HR: Ceed Sportswagon
HU: Ceed Kombi
IS: Ceed SW
IT: Ceed SW
LT: Ceed SW
LU: Ceed SW
LV: Ceed SW
MD: Ceed SW
ME: Ceed Sportswagon
MK: Ceed SW
NL: Ceed SW
NO: Ceed Stasjonsvogn
PL: Ceed Kombi
PT: Ceed SW
RO: Ceed SW
RS: Ceed Sportswagon
SE: Ceed SW
SI: Ceed Sportswagon
SK: Ceed SW
TR: Ceed SW
UA: Ceed SW
UK: Ceed Sportswagon

Optima
Only evidences so far is that Austria, Germany and UK use the Sportswagon name and France the SW name. Most probably they follow the same denominations used for the 2nd-gen cee'd.

For older models (Clarus, Pride and Rio) I will do a separate check, as the documentation is more difficult to be found.

* 2nd gen cee'd models are here listed with different codes [EU] and [JC]: which should be the right one?

I believe the Rio [DC] hatchback/wagon had no separate name in Europe (IIRC it was Rio5 in North America). Here it didn't, as it was the main model offered (the sedan was only briefly sold, and much less popular than the wagon/hatchback).
For the 2013+ cee'd, I'm finding JC on wikipedia. What do part sites report? I'm seeing [JC] for the hatchback and [JD] on the wagon on your searches from carter-cash

Some informations about Kia Europe's Zilina plant:
https://press.kia.com/eu/en/home/corporate/factoryslovakia.html
Also second generation Sportages were built there since 2007.

i don't remember for US but here the 1st gen wagon was named Rio RX-V

https://upload.wikimedia.org/wikipedia/commons/thumb/7/76/2003-05_Kia_Rio_RX-V.jpg/1280px-2003-05_Kia_Rio_RX-V.jpg

I found this thread in my long to-do list, I still have to process info posted here above.
If there are details to add, don't hesitate before I work on it

I updated the Ceed family and the Venga (and changed the default), but for the first-gen Pride you mean [DA] rather than [UB] I assume
For the Ford Festiva, many are already correctly listed, but many are missing the chassis code. Also, we have a mix of DA/WA, and D2/WB. Following Wikipedia, WA would be more correct it seems for that one. But where they all made in South-Korea? It is not fully clear.