First try the latest v7 beta version, it does have Linux kernel that’s current and should have drivers for latest hardware. See http://forum.mikrotik.com/t/v7-0beta8-development-is-released/140169/1
As for installing ROS, I found it easiest to boot ISO in vmware where I also share host device where I want to install ROS. I usually install it to USB flash drives, but it also works with USB to SATA adapters - just share the USB port with VM. What also works is making HDD image this way and then writing it to drive later, just be aware that HW ID and license depends on the serial number of disk where ROS is installed. So buy license only when it’s running on final drive and final server hardware… that’s why I usually install it to USB flash drives, as USB booting doesn’t depend on any special drivers and it’s well supported… and you can swap it between servers to test various hardware, without losing the license…