I know that Insight has recently just withdrawn from many of his games and I suspect that this one would have been first on that list. I have no knowledge of hafrogman's current whereabouts, but I have little hope that he will remain here long. Unfortunately, drothgery, that, I believe leaves you as the sole survivor.
If you want to continue, we can either attempt to recruit replacement players or you can take on the other characters as co-equal PCs or as henchmen/servants/employees of your PC, and you could even choose any of the characters to be your main PC.
Just spitballing here, so any other ideas are welcome.
Although I like Sariel's concept and the idea of running this adventure, I don't really want to play in a game where I"m the only player, even running multiple PCs or henchmen (even if it would let me set up the party entirely for Sariel's benefit and so have everyone else as Essentials melee basic attack-based builds). And we barely got started. If you want to reboot the game and recruit a full set of new players, I'm game (whether reusing Sariel or building someone new).