GPU AIO mounting and fans/power

[Invertigo]

So, I happen to have an AIO unused so been looking at getting the NZXT G12 kit to use it on the GPU. The only question I really have, how best to connect up the pump and fans to which appropriate sockets - it's an ITX system so the motherboard has one CPU fan header, one PWM/Pump header and one 3 pin (Technically 4 pin, but only has DC control and no PWM).

I'm also aware you can connect fans to the GPU header with an appropriate adaptor, considering this might be the option for the rad fans?

 

[Invertigo]

Thinking I could run both pumps off my PWM/Pump header, but would it be better to use a SATA powered splitter in this instance? I know running a couple of fans off one header is fine but dual pumps is a new thing to me.