Was Stephen Paddock an undercover FBI agent involved in arms sales to ISIS here in the U.S? Was ISIS responsible for the Vegas attack?

He was not an FBI agent, nor was he involved with ISIS in any capacity, directly or indirectly. This is just disinformation being promulgated for the usual reasons as it serves the interlopers and will not serve humanity to channel them in a false direction to solve this crime. ISIS had no direct effect or involvement in this episode. It was only the presence in the perpetrator's consciousness of the impact of terrorist attacks that created the idea for the mass shooting, and it was his preoccupation with guns from his karmic legacy of prior involvement, that added to the mix and ended with the tragedy at his hands in this manner. In a sense, it is a copycat but not because of ideology in alignment with the terrorists exploiting the Muslim faith. This was indeed, as stated in his channeled answers to you, a grievance about the gambling establishment. While he was an avowed high-stakes gambler, he was not fully happy with that preoccupation and was quite aware he was unable to control the compulsion and blamed them for this weakness in providing the ready means for him to indulge.