Reasonable, however It's more likely the Jem Hadar and Vorta would be completely lost without the orders of their gods. Also without the Founders it's more likely they would be a rebellion within the Dominion from the other species, I'd imaging that would keep the Jem Hadar and Vorta occupied.

If I were the founders (and of course im not)

The Jem hadar would have an over whelming conditioning

and in the event of the deaths of the founders it would kick in

Exterminate , Avenge , Restore

You're not a founder
In the show the death of either a founder or vorta (I can't remember which) causes the Jem Hadar to go on a death march, but a civil war would stop that.
Also could 31 not engineer a disease to wipe out the Jem Hadar or destroy the Ketracel white stocks?

yes 31 are stupid enough to try that

but you miss the point

the Jem hadar would Evacuate EVERY outpost , every colony
and march on us

After humanity was a greasy stain on the rug they would rebuild the dominion

as to knocking out the white
a Jem without white turns Killer guided missile

but of course earth would round up and execute 31 on mass for the Genocide of an entire quadrant

They are few Jem Hadar in the Alpha and Beta quadrants. The ones in the Gamma Quadrant would suddenly find a huge power vacuum on their hands and civil war, also they should have no idea who is behind the genocide, Section 31 are a secret organisation, they would suspect anyone including the Gamma Quadrant members of the Dominion.

without their masters they have no motive to retain control of populations

and of course they know EVERYTHING about section 31
especially as they had at least one infiltrator inside Starfleet command
And the evidence of Dr Bashir