I am broke enough to bite, but you need to be a lot more descriptive about what you want. You lost me after step 1: base it on the omega mod. After that, I am not sure what all else you want done.
If possible compatible with other mods too, like those that add new classes
Those 2 are, I think pretty straightforward.
Add a modifier for enemy health (ie: +110%hp)
For example:
Trash mobs (value 1)/Hero monsters (value 2) /bosses (value 3)
have:
100hp (value 1)/200hp (value 2)/300hp (value 3)
With this mod you could modify this value to be like this: [all enemy hp*1.1]
110hp (value 1)/220hp (value 2)/330hp (value 3)
Add a modifier for enemy resistances (ie: fire resistance +120%)
It should work exactly as the previous example
Trash mobs (value 1)/Hero monsters (value 2) /bosses (value 3)
have:
100hp (value 1)/200hp (value 2)/300hp (value 3)
With this mod you could modify this value to be like this: [all enemy hp*1.1]
120hp (value 1)/240hp (value 2)/360hp (value 3)
The way this works, you have to have the source for each mod that you want to merge. Then there are ways to modify the records to give you the resulting changes in HP and RES for the enemies.
But when you talk of ini files and compatibility, I think you do not understand, if you want a mod that has Omega + GrimQuest, you need to merge them at the start, you cannot make a mod based on Omega and then add in later another mastery mod, which is what I assume you mean by “make compatible”.
But not all mods, such as my GrimQuest example, are open source.
And what I meant by compatible is, did you see that the game only allows you to pick one mod at a time? Well, If you can merge it with another mod (open source) and it works, then it is compatible (at least that is how I understand it)
When you merge from source, there can be conflicts, but I have tools to resolve them peacefully. But are you sure you cannot get these 2 mods already in DAIL?