Generic vassal names still needed for:
Egyptian Respawn, Babylonia, Phoenicia/Carthage, Tamils, Ethiopia, Korea, Maya/Colombia, Vikings, Tibet, Khmer, Indonesia, Mali, Inca, Italy, Aztecs/Mexico, Thailand, Congo, Iran, Argentina, Brazil
How about
Kedatuan? They are old Malay term, (so it's suitable for Srivijaya). They have their own vassals and their own leader but still under grand leadership of a bigger empire (hence, the bigger empire's title is MAHARAJA, or literally MAHA = Great and RAJA = King.) Thai version of Kedatuan is
Mueang. It is like European "Principality of ..." so it could be Kedatuan of ... , Mueang of ...
You have to read
Mandala Wikipedia article too for a better understanding. I think it could be made so vassals use Kedatuan/Mueang (without "of") ... while the masters use Mandala of OR Kemaharajaan (Maharaja is a title, Kemaharajaan is noun)... but I'm not entirelysure. There's no real life example (because of Mandala system, they respect each other as center of regional power) but Khmer vassalizise to Indonesia as Chenla but in the game Khmer spawn before Indonesia so... (the original Khmer Empire is 800ADs, declared independence from Java (Indonesia))
Pinyin Chinese names still needed for:
Phoenicia /Carthage, Ethiopia , Maya /Colombia, Vikings, Netherlands, Mali, Portugal, Inca (Peru), Aztecs (Mexico), America , Argentina, Brazil
Phoenicia >> Feiniji
Carthage >> Jiataiji
Ethiopia >> Aisaiebiya
*Axum >> Akesumu
*Abyssinia >> Abixiniya
Maya >> Maya
Colombia >> Gelunbiya 哥倫比亞
*Gran Colombia >> Dagelunbiya 大哥倫比亞
Vikings >> Weijing 維京
*North Sea (Empire) >> Beihai (diguo) 北海 (帝國

*Anglo-Scandinavian (Empire) >> Anggelu-sikandinaweiya (diguo) 盎格魯-斯堪的納維亞 (帝國

*Kalmar Union >> Ka'erma (lianhe) 卡尔马 (联合
*Scandinavia >> Sikandinaweiya 斯堪的納維亞
*Norway >> Nuowei 挪威
*Sweden >> Ruidian 瑞典
*Denmark >> Danmai 丹麥
Netherland >>
Mali >>
Portugal >> Putaoya
Inca >>
Peru >>
Aztecs >>
Mexico >>
America >> Mei (guo)
Argentina >>
Brazil >>
Will update.
* indicates bonus. It didn't mentioned in your request list but I think could be important.
() indicates empire, nation, union, whatever... it is in the original title name but since this is vassal name so it should be omitted.
For example, instead of Meiguo it should be Protectorate Mei State, then Protectorate Ka'erma State... etc.
By the way, what is the name for "Moors as vassals to Norse" ??? If there isn't any, this could be a good alternative :
Kingdom of Nekor