What is the usage with these names?
道明寺, 花澤類, and 藤堂靜


All Japanese names:

道明 (Michiaki) is family name, 寺(ji/ Tera) is first name

花澤 (Hanazawa) is family name, 類(Rui) is first name 

類 sound strange in Chinese name, but it might have been Japanese 平假名 "るい" translated to 漢字. When a Japanese name contains 平假名 instead of Kanji, The Chinese translator would choose a Kanji with that pronunciation, and they usually have more than one choice. 
Take るい (Rui) for example, it can be one of the following Kanji: 塁 涙 累 類 泪 壘 羸 縲 瘰 誄 

累 and 泪 are female names; 壘 and 類 can be male names

藤堂(Todo) is family name, 靜 (Shizuka) is first name


  I think those are just the second syllables of the two-syllable given names.


If a Chinese name is made up of a one character last name and a two characters first name, you can use the entire first name or just the last character to address that person. 

Example:

You can address "劉志雄" as "志雄" 

It is not wrong to address "劉志雄" as "雄", but it is very informal. (use only to people who are very close to you)

In most cases, when addressing someone with his first name , we would add name prefix 阿，(as in 阿雄)