Zimbabwean playmaker Billiat joined the club from Mamelodi Sundowns on a three-year contract with an option of one further year, having rejected the offer of a new deal at Chloorkop.
Left-back Mirwa was brought in from ABC Motsepe League side Buya Msuthu FC on a three-year deal with a one-year option.
Offensive midfielder Andrianarimanana was recruited from Fosa Juniors FC in Madagascar. He has penned a two-year contract with a one-year option.
Andrianarimanana was selected as the best player at the recent COSAFA Cup, which was held in South Africa.
“It is with great pleasure that we welcome these players into the Kaizer Chiefs family,” said Chiefs football manager Bobby Motaung .