Ok, so your setup is right. But I'm only seeing one class curve created, which is the "Test".
The initial values for each parameter created on that class curve is not being applied on the actor?
Well, I think I will need a sample project from you, replicating the issue. Because I tested here on a new project, only Eli Book 6.1.2 and Class Curve 3.0.0, and it is working just fine.
Plugin parameters

Class note field

Actor in game

Your RPG Maker core files are updated to 1.10.0?
Upload to me a sample project somewhere and send me the link here so I can download and take a look
Plugin is working just fine on your project, with only EliMZ_Book and Class Curves ON:

Now, you have like a LOT of plugins.

When I enabled them, we got errors and the plugin parameters of my plugins are not even being processed. Which is crazy.

The compatibility issue is with Fossil. So I'm sorry but that plugin is too big and too messy for me to find a fix.
Now, when I disabled it, the parameters seems to be working, getting their values from the Class Curve:

I removed all the equipments from the actor, and that was the results above. Something else is changing their values. Every parameter should be 10, which is the Initial value on Level 1, but we can see "FP" as 11, M.Attack as 12, M.Defense as 9 and Luck as 11.
Propably something configurated on your plugins, and that you will need to figure it out.
What are you expect to happen when the plugin is enabled? Perhaps you misunderstood something about the plugin?