HTE and Haunting are of exactly the same difficulty and need around 32m raw attack stats (equivalent to 640k BTA att stats).
To succeed at almost zero troop levels, you'll need to have those as static attack stats, either from equip (BFE), allies (BFA), items and the castle.
In your case, you have a lvl1 castle giving no static attack, around 4m BFE att, and negligible allies. This means that you'll need to compensate around 28m raw att stats with items around zero troop levels (and 20m with full troops).
To succeed at almost zero troop levels, you'll need to have those as static attack stats, either from equip (BFE), allies (BFA), items and the castle.
In your case, you have a lvl1 castle giving no static attack, around 4m BFE att, and negligible allies. This means that you'll need to compensate around 28m raw att stats with items around zero troop levels (and 20m with full troops).