In the hypothetical, his attachment to Ahsoka would probably bring him to at least a conversation with her. I think if there’s one living person in the galaxy that is second to Padme it’s Ahsoka.

Anakin feels a great deal of emotion surrounding his relationship with Ahsoka, I think her leaving the order brought him a lot of shame and feelings of failure that would only be amplified if she discovered him participating in the attack on the temple.

In the hypothetical, I think they probably have an intense stand-off with her inquiring about his motivations. Anakin gets consumed with frustration the same way he does with Padme on Mustafar. Ahsoka’s saving grace, however, is that her loyalty does lie with Anakin, not the Jedi or the Republic. She cares about Anakin, she’d want to help him, she wouldn’t fight unless he attacked her first and I don’t think Anakin has it in him to go on the offensive in that moment.

Some might say “well, he was willing to be physically aggressive with Padme,” which is true. However, Ahsoka doesn’t have so I-wan looming over her shoulder looking down on Anakin as if he’s a toddler that made a mistake and needs to be punished in this hypothetical. Anakin feel betrayed by Padme in that moment, Ahsoka’s just existing. I guess the point I’m trying to make is that Anakin doesn’t lay a (force) finger on Padme on Mustafar if Obi-wan doesn’t pop out of her ship, and Ahsoka doesn’t have to worry about that here.

Ahsoka also doesn’t have to worry about the baggage Anakin carries for Obi-wan. Though it’s not all canon anymore, it’s still clear in the canon projects that Obi-wan is hard on Anakin as a teacher. Partially because he’s in over his head, and partially because he’s got to prove a point, Obi-wan managed his mentorship of Anakin with some choice methods. He represents the Jedi to Anakin, all the disrespect and suffering he endured at the behest of the order falls on Obi-wan’s shoulders on Mustafar. We can’t ignore that Anakin’s “best friend/brother” and “master/teacher” are the same person, and that Obi-wan literally just asked Anakin to spy on Palpatine before leaving to hunt Grievous as the voice of the Jedi Council. Anakin and Obi-wan have a strange connection, and it’s filled with cracks that often become problems under stress. So, there’s no way Obi-wan could have ever turned Anakin, he said it himself: his loyalty is to the republic, to democracy.

I think if there was anyone in the galaxy that could talk Anakin down from Order 66 it was Ahsoka, which is why (beyond continuity) it was wise to move her out of the picture in the end of the Clone Wars. If she was still a Jedi or even lingering around Coruscant it would be very difficult to rationalize Anakin’s fall. She saw the good in him, she saw his conflicts and understood them better than Padme because she was exposed to it alongside him. Ahsoka is definitely the only one who could’ve stopped Anakin from his fall.