The minisubmarines were part of the larger attack. The Japanese planned for a simultaneous air and submarine attack on Pearl Harbor in which minisubmarines, detached from their mothersubmarines at approximately 0100-0200 on 7 December and try to penetrate the harbor. All things considered, the minisubmarines were a stupid addition to the Pearl attack. Navigation of these submarines was nigh impossible and the question of them making an attack between the two airstrikes was optimistic thinking at best. Moreover, the minisubmarines could be spotted and potentially alert Pearl's defenses, denuding the air attack of surprise. Luckily for the Japanese, the minisubmarines only added to the confusion of US defenses and did not harm the Japanese raid.

So since technically, the US was the first to attack Japan, did this give the Japanese the final push to attack,

If we talk about JUST December 7th around Hawaii it is kind of true.

But this also ignores the long history of building friction between the nations. For instance there is the Panay Incident in 1938 when Japanese aircraft bombed and sunk a US gunboat anchored off Nanjing in China covering the evacuation of Standard Oil employees ahead of the Japanese attack on the city.

Just getting the carriers into position was a deliberate gamble that far from home and supply, the whole thing was already planned to happen.