I've recently revised the translated headers and, unfortunately, found some issues.
First of all, C headers were translated directly into Pascal modules (units), but, as it's generally known, they're quite different things. This happened because Pascal was a fairly new language for me, so I misunderstood some of it basic principles. Because of this, I decided to merge all units into one module.
Secondly, original ENet headers aren't separated into external (API) and internal parts, so I automatically translated some structure definitions that aren't needed for DLL usage. I've removed them from the revised version.
And thirdly, when C enum is just a simple grouping type so you can use its constants as they were simply macro definitions, this doesn't apply to Free Pascal where enums are entirely separate types. So I redefined those enums which were defined only for grouping purposes, to the simple constants.
So I've uploaded new version of the headers, and updated link in the first post.