The only requirement for this kernel is Oreo 8.1. By default, all of the spectrum profiles used will enable more then 4 cores. However, this can be modified. Read through this thread or see various release notes for details as to how to.
How many cores? What spectrum profile are you using? Battery / Balance use all 4 LITTLEs and 2 bigs; while performance and gaming use 4 LITTLEs and all 4 bigs. Both the hotplug drivers (HIMA and MSM) included in the kernel are disabled by default, they were included by request. Core control is on by default. I'm not sure what you mean by hexacore mode.
0 core stays on and the 4th core is on the rest is on/off, so while in use it turns all the cores on then it I don't do anything 0 and 4 core is on the rest is off. For me I don't use spectrum, I wouldn't know. And hexacore mode on EX kernel it doesn't stick anything, so I'm not sure if they app has any bugs or anything.