Warlord should not be a problem in my opinion. Many OGL products have classes that have similar or the same name as D&D. WotC can copyright the Warlord as a specific thing, but the actual Word Warlord should be able to be used in an OGL product.
Obviously, just as with the other classes (and this would apply to ANY class) it cannot be a copy and paste job and must be original and in accordance with the OGL.
As Warlord as a description of a military leader has been in use for over a millennia, I do not see a difficulty in using it in the same context as it's dictionary definition for a class that operates as a leader. It should be fine using it as a class name in relation to the dictionary meaning which WotC cannot copyright (unless they take a LOT more than simply one small group to court).
If people still feel it is problematic we could change it's term to Military officer or Regal, Noble, or something else.
HOWEVER...what I do not see being able to be done is to have the classes of Avenger, Invoker, or Warden be classes that are even similar to those in the PHB 2 as there is no historical context in the way the D&D made them as classes as far as I'm aware of.
We could have it as a Witch hunter, Avatar and Nature-born or something of the like instead, but those specific names as classes as described are specifically D&D with no historical aspect. I'm open to other names for them.
Tiefling and Dragonborn also cannot be utilized. I'm more likely to go with the term of Dragonmen or Dracs or Dracomen instead for Dragonborn...Tieflings on the otherhand...unsure.
We could call them infernals though that term has been used in D&D previously, but for something else...so unsure on that (have to check with my legal sources in that regard). We could just straight up call them Half-Devels or something of a similar line. Open to suggestions.
No Goliaths, Deva's or shifters either. Perhaps Half-Giants, Angel reincarnates, and Wolfman/Catman or something similar to those. Once again, open to suggestions.
