Interesting note: the one thing Bashir and the Jack Pack apparently did not anticipate--aside from the Breen alliance, which tilted the scale in the
Dominion's favor, mind you--was Section 31 in general, and the virus in particular.
Suppose that's something.
The virus could have also caused the Jam Hadar to launch a massive Kamakaze attack on the Federation and its allies in revenge and killed billions. Thank god Odo managed to save the Founders and get them to end the war and stoped those idiots.
Nice theory--except for the fact that in "Starship Down", it was established that if the founder dies, the Jem'Hadar who were entrusted to defend it all commit suicide. If they were really so "vengeful" as you claim, they would have, in that episode, killed all the Starfleet Officers on the planet...but they didn't.
And of course...the Tal Shiar was decimated by the Founders in "The Die Is Cast"--and the Romulan-founder explained to Odo that this effectively crippled the Romulans as a threat in and of themselves.
Again--the fact that Bashir was able to use his computer console in "Extreme", as opposed to "Inter Arna...", hints that something was amiss. The only reason Sloan would
allow himself to be caught implies that there was something else going on.
Not neccessarily. As Scotty said in STIII:TSFS, "The more they overthink the plumbing...the easier it is to stop up the drain."
Because she was not an ally. She just supported the alliance while it suited her. Need I remind you...of the opening arc of season 7--and how Senator Cretak, your "ally", nearly destroyed the alliance over a few Romulan weapons in the Bajoran system?
Yes because people are never forced to go along with their government's bad ideas so as not to be a traitor, you also realize oh so blind one that when Barshir thought 31 was planning to kill Koval she tried to help him stop them to prevent the Federation and Romulans from going to war.

..."Barshir"?
Anyhow...remember, as Ross explained, Cretak only did what she thought would advance the interests of the Empire. She thought it would benefit the Empire to put weapons in the Bajoran system--and she thought that the assasination of Koval would hurt the Empire.