Some cheap puns here involving overlap with the names, so I've spelled things out... the Japanese here is pretty basic "Japanese 101" stuff, the type of phrases you'll find in a phrase book and are good to know.
KonichiHatate
Konichiha (the "ha" is pronounced as "wa" for archaic reasons): Good day!YoshiYoshika
Yoshiyoshi: There, there (standard thing to say while patting someone on the back to console them)TadaiMarisa
Tadaima: I'm home! (standard thing to say when returning from work)GanbaReimu
Ganbare: Fight on! (a standard cheerleader saying)Shang-High Touch
High Touch: High Five
OkaEirin
Okaeri: Return/Welcome (okaerinasai (note that the character used there is "na" not "n") is the standard way of saying "welcome home")