Computer Storage Geeks Needed here!

I am trying to learn and since i have nothing to tell me whether i am understanding anything i "Assume" to be true or not, i need guidance, hehe.

We all know what a disk array is, a backplane, etc....I want to build my own and have the edge that it will be cheaper compared to it's expandability potential.

I need it to be standalone so lets start from scratch and fill me in on anything here.

I will acquire a case with many 5.25 external bays for the purpose of using backplanes.

Found an awesome deal for a backplane that uses 3 bays for 4 SATA drives for under $100 with great reviews so it's sold me on that.

Now, without a motherboard required, i install a PSU that is strong enough to power as many drives as i want. I do the PSU wire trick so i can turn on and off the system via kill switch on the PSU itself.

Question #1-

Is it safe to power off all the drives via the PSU switch when i am done with the drives? I do not know what's different when it comes to doing a hard shutdown(kill switch) or when using an OS and letting it shut down

Now, i have the backplane installed with all proper wires feeding into it...

Let's say i have 4 drives, for example.

Can I do the following with success?

Run 4 sata cables from the backplane into this-

Please read description

Then run them out of that case via that bracket into a real computer using the SAME bracket? Then take it's 4 internal ports directly down to the motherboard?

Or use that bracket and run all 4 cables out of it into this-

SATA External Port Multiplier Official Website

Then from there.. into an esata to internal SATA bracket that would run directly to sata port on motherboard.

Remember, if you forget or do not know, this is to NOT require a motherboard in the external storage system and NO PCI RAID controllers of any kind in a pc that it connects to. Any pc it connects to will have RAID support on the motherboard.

Also note - ALL drives will always be ran JBOD and JBOD only so if i list any type of wiring configuration that may make that impossible, let me know.