NAS upgrade (HDD compatibility question, chassis/Case recommendation)

[DarkStroker]

Hi. I have some quick questions:

Currently i run an old FreeNAS build with a zfs zaidz2 pool with 6x 8TB HDDs.
Those are Geli encrypted and i can’t upgrade the pool or OS. So i thought i make a fresh pool and OS.
Drives are Hooked up to a Dell H200 flashed to IT Mode.

I wanted to add 2 new HDDs and do a raidz1 with 8x8TB (since i have my important stuff backed up somewhere else too)
The 6 x 8TB HDDs are Seagate Enterprise Capacity ST8000NM0065 SAS drives 4KB (native?)
I also bought 1 Toshiba Enterprise 8TB (MG06ACA800E) SATA 512e and
1x WD Whitelable WD80EDAZ-11TA3A0 Sata (idk if 512e or 4KB)

I know i can mix Sata and SAS drives. All are CMR and none SMR. But what i forgot and never fully understood was 512e/4KB compatibility.

Will i be fine with this configuration? Mixing 512e and 4KB (no 512n) Drives?

Drives are currently in a Dell R710 server. I wanted to build a new quieter dedicated NAS.
Thats why i am currently looking at new Case. Desktop or server. I don’t care as long as there are 8-16 drive bays and i can run it somewhat silent.
(I sleep in the next room)
16 bays would be awesome for future expansion. Hotswap would be cool but not really needed if i can easily remove a panel with 2 thumb screws.
If its possible to use ATX or miniATX boards and fullsize ATX PSUs i could use my old ivy bridge PC and would basically only need a case and no new hardware.

Does anyone have a recommendation for good NAS cases? 8-bay up, quiet

Thanks in advance guys

[NZSNIPER]

Define R5 — Fractal Design Can fit 10 3.5" drives with 5.25" to 3.5" adapters.

[rcxb]

Antec P101 Silent (8x3.5"): Antec Performance Series P101 Silent Black 0.8mm SPCC ATX Mid Tower Case with 8 x 3.5" HDD / 2.5" SSD Removable Bays - Newegg.com

Phanteks Eclipse P600S (10x3.5"): Phanteks Eclipse P600S PH-EC600PSC_BK01 Black Computer Case - Newegg.com

Are you sure you’ve tweaked the power/fan settings in the R710 up to the quietest they can be? How about swapping the fans with quieter aftermarket units? Admittedly the old CPUs in the 710s are hot, so an R720 would use less power, running cooler and quieter (and offers two more drive bays), and they’re cheap. An R720XD adds another row of 3.5" drives for 12 in total if you’re interested in expansion. Yeah, not silent, but I’d think good enough for “in the next room” use.