Excellent analysis.
The Iranians also have one thing we may or may not have contemplated. Access to our troops.
For years the Iranians have made threats but havent had direct access to US military assets they can attack. We had the advantage of standoff distance and they had no weapons capable of hitting our assets anywhere in the world.
Now, if they do have nukes, they have large concentrations of US troops within 500 miles range, and they have multiple platforms that can deliver them.
Small nations gain initial advantage on large nations by staging pre-emptive attacks and degrading the opposing force ( cutting it down to size). This usually comes as a surprize attack.
Pearl Harbor comes to mind as one example.
I wouldnt disregard the threat from Iran. They dont operate within the bounds of common sense.
In order for Iran to take Israel conventionally, they'd need to take Iraq. In order to take Iraq, they'd need to take us out, both ground and naval forces. Since it's become apparent that they're sending missiles to hezbollah via Syria, we already know that they are actively involved with Israel. The only way for them to go is deeper; they'll not withdraw or back down.
Since they can't use subterfuge or technology to sneak past us to get directly to Israel, They are possibly going to attempt to bog us down on the ground, and maybe punch a hole in our naval forces. A nuclear attack on a carrier would be a possibility. It would at least allow them a window.