No.
Severus made this statement, "Can have S draw up memo on Turkey...". Severus is talking about S, either asking if S can draw up a memo or that he could have S draw up a memo, to which Juuno later approves, and advises Severus and the others.
Juuno later joins the conversation and says he is with S in GT. He is telling Severus that. Unless Severus and S can be in two different places at the same time, then S is not Severus and Severus is not S.
Your S theory is hereby debunked.
Is Juuno “juiles”?
Is Juuno “juules”?
Or, S could have two meanings, referring to someone outside the conversation as well as to Severus. It is true that Severus refers to S, but it’s also true that Huck asks the question “..S, you in here?”. Also, Juules’ comment that he’s with “S” is totally consistent with “S” being Severus. Juules and Severus could be in the same room on separate devices. After Severus makes a comment, Juules chimes in for the first time in the conversation, letting the rest of the people know he’s sitting next to Severus and has been lurking the whole time.
I’m thinking “S” is Strzok and “Severus” is Soros ... other anons speculating McCabe is in on this too (Hawk?)