Traditional and Simplified characters
Do you speak about Portal:Cpx for Puxian Chinese (where the user wanted to indicate that it is enabled with a "mixed script", rather than requesting for separate namespaces for Latin, Simplified Han, and Traditional Han scripts, and then sorting the translations)?
For now it seems that most or all translations have been made using the Latin script (but Kahin He started to translate in the [cpx] using Han characters, creating the mix); I'm not convinced that [cpx] should be "mixed script" like he indicated with the generic script code "Zxxx" for undetermined scripts: these 3 scripts are clearly determined and should be correctly identified in translations, independantly of the existence of some fallbacks from one script to another in the same language, or to another language like Min Nan, when there are missing translations.
Since the beginning, [cpx] used Latin as its default script (as it was initially requested). So [cpx-Hant] or [cpx-Hans] should be used for these new translations using Han characters (just like with other Chinese languages, where [zh] was deprecated and sorted by script, making a possible extension for [zh-Latn], i.e. romanized with Pinyin by default or possibly using IPA-based or Wade-Giles romanizations with an additional code extension; on the opposite [nan]=[nan-Latn] still uses Latin by default and it is wellknown and used with a standardized Latin alphabet; [nan-Hant] or [nan-Hans] should be used otherwise and not mixed into translations for [nan]=[nan-Latn]).
But Wikimedia Incubator also does not distinguish scripts for that Puxian language: incubators started for Wikipedia or Wiktionary are using both for "essential" portal pages (the distinction is made article per article), there's still no separate wikis and no clear indication whever the Han-written texts are simplified or Traditional, and still no transliterator and variant selectors like there are in Mandarin/Chinese wikis [zh]; so readers have to "guess" (for Min Nan and Hakka written in Taiwan, Hong Kong and Macau, this is most probably Traditional Han, but for others this is not clear; however Simplified Han is rapidly gaining standard support for non-Mandarin Chinese languages in Macau and Hong Kong; I don't know if Simplified Han starts gaining support in Taiwan, notably for Mandarin and Hakka, the two major languages, whereas other native Austronesian languages in Taiwan are developping now a Latin-script standard).
Also note that [Hans] and [Hant] are not really distinct scripts, but different subsets of the [Hani] script, with a large common intersection (and for most characters that are different in these subsets, there are transliteration rules implemented in Mediawiki in order to support two existing orthographic standards for Mandarin, and probably not accurate or relevant for most other Chinese languages). If Puxian Chinese does not really standardize any difference between [cpx-Hans] and [cpx-Hant] and accepts both indifferently, then [cpx-Hani] should be used instead of [cpx-Hans] and [cpx-Hant] (and here also this is not a situation of "mixed script"), just like what is done in Japanese (using only some traditional "Kanji" forms), Korean (using only some traditional "Hanja" forms), and Vietnamese (using only some traditional "Chunom" forms as well): we get for example [ja-Hani] for old Japanese texts not using kanas Simplified Han does not seem to be used in Japan, Korea and Vietnam, because they don't really need it (they already have standard Kana, Hangul and Latin scripts widely used; the "Bopomofo" syllabary used in China, similar to the two Kana scripts in Japan, is primarily meant for basic learners of Mandarin and has not gained large use, except in ruby annotations of Han-written school books as a common alternative to Latin-Piyin ruby annotations; but may be Bopomofo is used on Chinese social networks and instant messengers, as a faster way to communicate, rather than using Pinyin-based input methods for Mandarin written in Han).
Similar consideration should be used for other traditional Southern Chinese languages (some of them also using other Asian scripts, such as Yi syllabary, Myanmar/Burmese, Tibetan, Arabic, or even Traditional Mongolian and Cyrillic in Northern or Eastern borders of China, even if Simplified Han is frequently used now along with Pinyin romanization for its input method...)
I think the problem is that there's no any true official formal writing system for Puxian Language, because no people nowadays use Puxian Language to Write for daily use. Most native Puxian speakers regard Puxian Language as a spoken-only dialect. So that those who write articles in Puxian or visit Puxian Wiki are just for linguistics hobby, linguistics research or dialect conservation. Most all Puxian speakers can speak another language (Chinese, English and so on), so there's no need to invent a Orthography for Puxian Language. There's also few books or other anything written in Puxian Language, except The Bible (Written by western missionaries hundreds of years ago), and some article written by Puxian linguistics hobbyists (just for hobby or for dialect conservation). Those hobbyists in China may prefer Chinese Character System; while those in other countries may prefer Latin System more.