Oh man, I wake up here in California and every day it seems like you guys had a party while I was sleeping
These are the cables:
https://www.amazon.com/gp/product/B018YHS8BS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The cable appears to be able to be inserted in either direction on the motherboard. The only locking mechanism if you want to call it that is the clip that clips to the connector housing.
I've had good luck with the cable matters and cable creations "low cost" SFF-8087 to SFF-8088 cables.
When I click on the link for the cable, Amazon helpfully reminds me that I've been buying them. In fact, I have four of those in one of my chassis right now and they've been working well for me.
I'm not familiar with your chassis and don't know what you've got for power supply. But, if your drives don't settle down and stay "visible", you may want to try testing them with the SATA data cable connected to them directly. You'd need a spare SATA power plug from the power supply of course and I don't know if you have one.
For ESXi download. Here's how I get there: After logging in, I select "Downloads" from the horizontal menu bar. From there, I select:
"Free Product Downloads"-->"Vsphere Hypervisor"---> click "Register" in the product description field--> Complete the registration page (you need to register for each free product, even version changes)--->following registration it takes you back to the "Vsphere Hypervisor" page you just left, but now your downloads will appear at the bottom of the page for "manual download".
Since I hadn't tried Version 7.0, I just did it myself to make sure it still works .
I mention this because if you enter the menu system via "Products" instead of "Downloads" on the menu bar you can't easily get to download the free product you want (at least I can't) on a free account. The way I describe, you can just get into the system to download free ESXi without checking out trial software. At least that works for me.