Thanks for your service there. I do believe if it came down, we would be able to keep the straits open. They could cause damage in the short run since none of them have any problems with defiling the gulf with fire, wrecks and oil.
It is pretty tight through there, but the traffic is well managed...
You don't need piloting services unless you are a complete goob who can't steer and follow a chart...
The "smaller" cross traffic could cause some heartburn, but tactically it would be easy to clog it up, yet fairly easy to clear it, or steer around any appreciable problems...
Iran used to have, and I'd need to confirm, but they used to have these "big" Silkworm anti-ship missles...Not the mis-nomered C-802's that the Chinese are selling to them, some can be airlaunched, but that can be countered relatively easy...Those big landbased Silkworms are problamatic in that they are really huge...Almost as big as a "small" fighter, they are relatively fast, and in that short of an operating area could give you some problems...They also have a pretty big warhead, about 2000 lbs. of high explosive stuff, plus residual fuel makes for a pretty big bang...
But with all of that, the Iranians don't have much more that can't be dealt with in a decisive manner...I certainly wouldn't want to be around one of them when the bullets start flying...