I appreciate the context and description of what you're trying to achieve.
In Core3 as it stands, there are different options as to how you want Jedi to be unlocked, be it the village from the point that Core3 is trying to emulate, to the original hologrind that you're looking to achieve. Core3 created its own hologrind which ties in with the new system for Jedi that Publish 9 implemented. The hologrind will skip the village and put you right where you'd be as if you just defeated Mellichae at the end of the Village quests.
If you are looking to perfectly recreate the Pre-Publish 9 Jedi experience, you're sadly out of luck. The very client executable file itself was modified that did away with the concept of unlocking a Jedi-specific slot for which you can create a new character. Until the distant and unlikely day that the client itself can be fully reverse engineered and decompiled, we will never be able to unlock a Jedi slot. The character who unlocks Jedi will be the Jedi that you have. This is because the code that allowed for you to have a Jedi slot was removed by SOE back in the day. We do not have a way to edit this back in.
If you're looking for the Pre-Publish 9 Jedi gameplay of having a long line of class trees instead of different options like it does now, you can re-implement that, but it might take some work, tweaking, and know-how of how skills, commands, skill mods, and abilities work. It can be done, but it does need some elbow-grease to get working. However, as I said before, it'll never be perfectly the way that it was, because the functionality of a special Jedi slot was removed.
As a quick aside though: Nothing is quite stopping you from creating your own Jedi unlock system from scratch, if you felt so inclined!