I'll merely list the steps, but you're going to have to make sure you've reviewed Kael's Modding Guide to get the exact know-how on how to do it.
1. The DLC wonders names are "BUILDING_STATUE_ZEUS", "BUILDING_TEMPLE_ARTEMIS", and "BUILDING_MAUSOLEUM_HALICARNASSUS". In order to get your mod to work for anyone, you have to delete these assets from <Buildings>.
2. Next, you'll have to create new buildings. Use similar tags. For example, in Ancient World, I used "STATUE_OF_ZEUS", "TEMPLE_OF_ARTEMIS", and "MAUSOLEUM_MAUSOLUS". Name them whatever you what, as long as you can identify them.
3. Create the effects and text files for the new buildings. Assign art from existing buildings (like TEMPLE, or HEROIC EPIC) or whatever to these buildings. Create your own custom icons, ask around for some, or use vanilla icons.
4. Make sure you assign techs for all the new buildings, and then create an entry in Building_Classes for each of the new buildings, and make sure <MaxGlobalInstances> is set to 1.
5. Make sure you've correctly enabled all XML files in ModBuddy through the Properties tab, name your mod, description it, test it, then release it.