Pre-Install Configuration suggestions - File System, Cache Pool, etc.

Hi fellow Unraiders.  New user here, just getting ready to install unraid for the first time.  Here are some details to what I am looking to use and do with unraid.

Hardware (this is already set)

• Supermicro chassis with 8x hot swap drive bays
• Gigabyte consumer motherboard with intel 9700k cpu
• Dual 10G SFP+ NIC
• Hardware minisas 2-port sas/sata controller (8x sata drives)
• 9x 12TB Sata drives (7 in array, 1 parity, 1 spare)
• 2x Segate Firecudu m.2 NVme drives
• 2x Team Group 512GB SSDs

Unraid use

• 80% plus of the usage will be for running Channels DVR (similar to Plex).  Will be recording and streaming frequently to multiple devices (most to internal netowrk, some external)
• Will use Docker for Channels DVR and some other programs (radarr, sonarr, etc.)
• May experiment with VMs, but I have no planned use for VMs yet.
• I am using home assistant, but have that on a small NUC and will likely keep it there.

Goals

• I prefer using XFS for the main array.  Mainly for the ability to keep most of the drives spun down when not in use.  With 9x mechanical drives, keeping them on will use a signifcant amount of extra energy.
• Would like to maximize responsiveness when streaming media on my local network.  This doesn't require much, but I am concerned how long it might take for the mechanical hard drives to spin up.
• Backup the unraid arraid to my Qnap NAS
• Easy file recovery.  If one drive fails, 

Questions:

• Is there anyway to improve read performance in an xfs array?  I've read about slogs, arc, etc. but those seem to only be available if using ZFS on the array.  Again, I would like to spin down drives that aren't in use so I don't think ZFS is for me.  Plus, I would like the ability to add another drive one at a time.  I would be ok with havig to add 2 at a time if needed.
• I would like to use the 2 nvme drives in a mirroed array and use them as a write cache.  BTFS or ZFS?  What would work better?  What are the pros and cons?
• Not sure what I want to use the SSD drives for.  A read cache would be great, but I don't know if that is possible when using xfs on the array.
• Is there any way to minimize drive spin up time, especially for media?  It wouldn't be good if I have to wait 10-20 seconds while the drive spools up anytime I want to watch a show.
• Drives in an XFS array don't spin up one at a time, do they? I saw some video where media was located on say the 8th drive in the array.  While this was an older video, drives 1-7 had to spin up one at a time first before drive 8 spun up.  It doesn't still work this way, does it?
• I have a 128GB Samsung Bar plus usb flash drive.  Can this be used for Unraid?  I have seen a max 32GB limit, but those aren't readily available.
• Is ther any benefit to using a 3.1 USB port on the flash drive (speed), or should it be on an older 2.0 USB port?

Any insight would be greatly appreciated.  Getting ready to get unraid fired up.