Can Taxed Dry be attached to the KOTHH agenda and utilised ?

Taxed Dry : Attach to an opponents income providing card.

If it is winter, attached card does not provide an income bonus

If it is summer, when you count income, you may also count the income bonus on the attached card

Well, technically KotHH makes a player's House Card GAIN the various income, influence and initiative bonuses. So it's the House card, not the agenda, that is the income providing card you want to put Taxed Dry on. Nothing wrong with that, though.