Use Wintersun and worship Rahjin-Khajiit is rich!
MQPaarthurnax 100
should work for the task at hand. With it, I kept Paarthurnax alive and I stayed friends with the Greybeards. Haven't checked with the Blades, but I'm quite sure they are friendly.
<p>Only issue, the "Why should I kill Paarthurnax" and so on stays. Everything else seems to work just fine. It shouldn't hinder anything else, expect leave those dialoge lines.
</p><p>EDIT: Be sure to save before you do this, in case something does mess up.
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