Here's the code with the naming pattern you requested. The parentheticals came from jeffjl's original post. Yes, the easier heroic version is simply called "Heroic" rather than the typical "Heroic I".
Code:
<ImageStyle Name="exp20_dun_darkpaw_scaled_solo_0" displayname="Darkpaw Warrens [Solo] (Lower)" menugroup="Karan" zonerect="-157, -354, 140, -9" heightmin="-100" heightmax="-53.46" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_0.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_0" displayname="Darkpaw Warrens [Heroic] (Lower)" menugroup="Karan" zonerect="-157, -354, 140, -9" heightmin="-100" heightmax="-53.46" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_0.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_0" displayname="Darkpaw Warrens [Heroic II] (Lower)" menugroup="Karan" zonerect="-157, -354, 140, -9" heightmin="-100" heightmax="-53.46" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_0.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_solo_1" displayname="Darkpaw Warrens [Solo] (Entrance Level)" menugroup="Karan" zonerect="-73, -318, 186, -18" heightmin="-53.46" heightmax="-20" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_1.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_1" displayname="Darkpaw Warrens [Heroic] (Entrance Level)" menugroup="Karan" zonerect="-73, -318, 186, -18" heightmin="-53.46" heightmax="-20" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_1.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_1" displayname="Darkpaw Warrens [Heroic II] (Entrance Level)" menugroup="Karan" zonerect="-73, -318, 186, -18" heightmin="-53.46" heightmax="-20" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_1.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_solo_2" displayname="Darkpaw Warrens [Solo] (Underpaw and Ancestral)" menugroup="Karan" zonerect="-154, 42, 108, 346" heightmin="-34.72" heightmax="-20" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_2.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_2" displayname="Darkpaw Warrens [Heroic] (Underpaw and Ancestral)" menugroup="Karan" zonerect="-154, 42, 108, 346" heightmin="-34.72" heightmax="-20" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_2.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_2" displayname="Darkpaw Warrens [Heroic II] (Underpaw and Ancestral)" menugroup="Karan" zonerect="-154, 42, 108, 346" heightmin="-34.72" heightmax="-20" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_2.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_solo_3" displayname="Darkpaw Warrens [Solo] (Upper North)" zonerect="-95, -269, 142, 6" availablerect="-95, -269, 142, -20" heightmax="25" heightmin="-20" availablerect="-197, -271, 233, 231" availablepriority="2" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_3.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_3" displayname="Darkpaw Warrens [Heroic] (Upper North)" menugroup="Karan" zonerect="-95, -269, 142, 6" heightmax="25" heightmin="-20" availablerect="-197, -271, 233, 231" availablepriority="2" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_3.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_3" displayname="Darkpaw Warrens [Heroic II] (Upper North)" menugroup="Karan" zonerect="-95, -269, 142, 6" heightmax="25" heightmin="-20" availablerect="-197, -271, 233, 231" availablepriority="2" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_3.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_solo_4" displayname="Darkpaw Warrens [Solo] (Upper South)" menugroup="Karan" zonerect="-245, -40, 120, 384" availablerect="-245, -20, 120, 384" heightmax="25" heightmin="-20"availablepriority="1" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_4.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_4" displayname="Darkpaw Warrens [Heroic] (Upper South)" menugroup="Karan" zonerect="-245, -40, 120, 384" heightmax="25" heightmin="-20"availablepriority="1" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_4.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_4" displayname="Darkpaw Warrens [Heroic II] (Upper South)" menugroup="Karan" zonerect="-245, -40, 120, 384" heightmax="25" heightmin="-20"availablepriority="1" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_4.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_solo_5" displayname="Darkpaw Warrens [Solo] (Terraports)" menugroup="Karan" SourceRect="0,0,436,506" zonerect="-196, 125, 36, 393" heightmin="17.44" heightmax="31" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_5.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_scaled_5" displayname="Darkpaw Warrens [Heroic] (Terraports)" menugroup="Karan" SourceRect="0,0,436,506" zonerect="-196, 125, 36, 393" heightmin="17.44" heightmax="31" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_5.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_5" displayname="Darkpaw Warrens [Heroic II] (Terraports)" menugroup="Karan" SourceRect="0,0,436,506" zonerect="-196, 125, 36, 393" heightmin="17.44" heightmax="31" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_scaled_solo_5.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_hub_0" displayname="Darkpaw Dugout" menugroup="Karan" zonerect="-63, -329, 45, -203" >
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_dugout.dds" SourceRect="0,0,436,506" />
</ImageStyle>
<ImageStyle Name="exp20_dun_darkpaw_tradeskill_0" displayname="Darkpaw: Sabotage [Tradeskill]" menugroup="Karan" zonerect="-157, -354, 140, -9">
<ImageFrame Source="images/maps/map_exp20_dun_darkpaw_tradeskill.dds" SourceRect="0,0,436,506" />
</ImageStyle>