I don't think there is any delay creating or joining a joint, at least, the way I did it for my Stickman game.
For me it was like:
On Enemy Created:
Enemy.Create Revolute Joint at ImagePoint1 to Leg1
Leg1.setAngle to 240 degrees
Now, if my Leg1 had any delay in getting created or joined, then its SetAngle of 240 degrees command would automatically be skipped, but it didn't. Which means it used to create the joint instantly, then also goes and follows the next Action.
You can easily have an "Add to" variable (of Joints), after the "Create revolute joint" and it will be executed accordingly.