Police pounced on a 15-year-old Springvale boy, 14-year-old Mulgrave boy, 16-year-old Mulgrave girl and 16-year-old Pakenham girl in simultaneous home raids early on Friday.
They will be interviewed over an aggravated burglary in Wonga Park, along with an attempted arson attack at a Mill Park restaurant and the torching of a tobacconist in Ballarat.
A white Isuzu D-Max and silver Ford Ranger were stolen from a home at Wonga Park in Melbourne's outer northeast overnight between February 19 and 20.
The Ford Ranger was then used in a firebombing on the Emerald Reception Centre in Thomastown on February 22, causing millions of dollars in damage.
The car was found burnt out about 2.5km from the crime scene in Bundoora less than half an hour later.
A 20-year-old St Albans man faced court on Thursday after being charged over the attack.
Police allege the other ute was involved in an attempted arson at a Mill Park restaurant in the early hours of Tuesday morning.
It reversed towards the front door of the venue and several occupants exited, before one reached back in to remove a jerry can.
The would-be arsonists fled after a witness ran towards the scene.
The same vehicle was then used the following morning in an arson attack at a tobacconist on Sturt St in Ballarat, leaving it significantly damaged.
The ute was later discovered burnt out on Eureka St.
Taskforce Lunar is investigating more than 30 fires linked to a conflict between warring crime syndicates over illegal tobacco profits.
Detective Inspector Graham Banks from the taskforce said police hope the arrests would provide further avenues of inquiry.
"We're seeing these syndicates recruit a range of people - including children - to commit incredibly serious and violent offences," he said in a statement.
"This remains of significant concern for police, and we will do absolutely everything we can to target those involved in this offending at all levels."
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