ASRock B450M Pro4 additional fans?

I'm thinking about installing more fans and I wanted to check what I'm going to do makes sense. So first of all, here is the specifications of my mobo:

CPU Fan Connector (CPU_FAN1)

CPU/Water Pump Fan Connector (CPU_FAN2/WP)

Chassis/Water Pump Fan Connector (CHA_FAN1/WP)

Chassis/Water Pump Fan Connector (CHA_FAN2/WP)
Chassis/Water Pump Fan Connector (CHA_FAN3/WP)

The last 4 connectors can be all detected whether they are 3-pin or 4-pin, all of them can be controlled by Smart Fan Speed Control and have (2A, 24W) maximum limitation.

Now I want to add 2 more fans, and the remaining headers are CPU_FAN2/WP and CHA_FAN1/WP. I'm not sure if I can just put 2 fans into those slots, in particular I'm not sure if I can put it in the CPU_FAN2 header. I think I can just put it there and make it target for the mobo temp in the UEFI but not so sure about it.

Also about fan splitters; the fan I'm looking for is Noctua NF-S12B. The product page says the max current is 0,075A, so this means I can use a splitter to connect two of them into a single header, right? Those fans are pwm, but regardless of the fact, I should be able to regulate the speed in the UEFI, am I correct? In fact, if the information is correct, I should be able to connect something like 4 fans into 1 header without a problem...

I just wanted to be sure since this is my first time installing additional fans with my first build. Any helpful information would be appreciated!