Ranging from - as in some are one , some the other, some in between. Haven't started replacing any yet. It's a legacy system I just installed the DVR for.
I picked one up but sold it already (for a 5 camera system) and what a sweet little package. I did open it but didn't look to see if there were more SATA connections. If there were, you wouldn't be able to get another drive in there - you would have to run a cable out of the box to a drive.
The main SSD is a M.2 (similar to pci) and the 2nd drive is a 2.5" sata. So, there is only One 2.5" and One M.2, just to be clear.
No VGA on the unit I got but does have display port - I just used a display port to VGA adapter.