Current ESXi user attempting to try unRAID with some questions

Hello everyone! Super unRAID noob here :-)

So my current home lab is running in the free version of ESXi and all is well. My basic workloads (Plex, a CentOS DNS server, a Debian Ubiquiti controller, a Debian general utility server) all run perfectly with boatloads of headroom to grow for my other projects.

But, one thing I'm REALLY interested in is GPU pass thru for virtualizing my existing desktop used for gaming. I love the idea of having a beefy virtualization server able to host all of server needs PLUS allow me to game all housed with a single case. This would hopefully also allow me to more easily stream things to my Steam link devices in my house.

So here I am about to try it out and I wanted to first ask how I should setup my system to prove out the ability to vitalize my gaming machine from a storage perspective... My setup is as follows

Intel E3-1230 v5

Gigabyte MX31-BS0

32GB DDR4

1x3TB HDD

2x2TB HDD

2x512GB SSD

1x120GB SSD

Nvidia 970 GTX

Seems like the docs recommend using my SSDs as the cache disks then I use the 3tb HDD as the parity drive and the others as the data? Would that provide the best IO?

Also, a few other questions:

1) Does the GPU draw power when the VM it is 'passed through' to is powered off? Considering I'm not home all the time, I'd hope that the GPU could power off so as to keep the setup somewhat power efficient.

2) Could I pass through the on board USB 2 controller or would I need another PCI controller to successfully pass through USB to support my keyboard and mouse for the gaming VM?

Thanks so much and looking forward to testing things out!

1) Does the GPU draw power when the VM it is 'passed through' to is powered off? Considering I'm not home all the time, I'd hope that the GPU could power off so as to keep the setup somewhat power efficient.

Would be interessting for me too.