Saudi Arabia, Oman and the UAE will not be affected by the blockade on the Strait of Hormuz. Qatar, Kuwait and Bahrain will be hit hard. Kuwait and Bahrain are already dependent on Saudi Arabia for nearly everything. So, it doesn't change much for them.
I think Qatar is going to be hit the hardest, becoming fully independent on other countries and having a history of problems with the Saudis in recent years, I think that's why they're panicking so much and it's why they are so eager for Iran and the US to sign the deal. They're also very vocal about the issue of the Strait of Hormuz.
So, Qatar will be the biggest loser of all this. Saudi Arabia and the Emirates, not so much. They already have sea ports that enable them to bypass the Strait of Hormuz.