BUR #21906 has been approved by @evazion.
create implication oounabara_to_wadanohara -> funamusea
create implication haiiro_teien -> funamusea
create implication mogeko_castle -> funamusea
create implication ice_scream -> funamusea
create implication sutare_yume -> funamusea
create implication taiyou_no_jubaku -> funamusea
create implication carnival_rhythm -> funamusea
The funamusea tag is currently used for characters from funamusea (artist)'s work whether they're from the manga, games or simply just characters that haven't yet made their debut outside of doodles or webcomics. Aside from serving its purpose for the aforementioned reasons, all of these characters share the same universe. And these aren't simply just cameos/references, they have important roles in all of these series. (e.g. Idate (Ice Scream) aside from being the protagonist of Ice Scream is also one of the main antagonists in Oounabara to Wadanohara, and Ivlis (Haiiro Teien) is a main character in Taiyou No Jubaku as well as the recently released Seaside Dispatches manga).
Taking this into consideration, I think all of these series should automatically have the Funamusea tag the same way Project Moon media has its own umbrella tag, since the characters aren't from one specific media, they're all part of series which share the same universe.
Updated