There's almost no possibility that it isn't Dan.
The idea that someone would, four years ago, stage a video using someone who sounds a whole lot like Dan to gawk over a hot tub and fantasize about having sex in it, then make a fraudulent text conversation, only to use it now? Two years after allegations started to come out? That's so unlikely it's comical.
And if it's faked, why not shoot farther? In this scenario, you have someone who sounds EXACTLY like Dan Avidan and you have the plans to ruin his reputation. Go full-on and make make a fake sex audio tape, phone calls, creepy answering machine messages, etc. Why stop at "I wanna bang you in my jacuzzi"?