While I agree that hitting is not an option, he has the right to get angry. But a lot of kids aren't told they're allowed to feel this way or that way... And the appropriate response to those feelings. I also agree that it's good to let your little man know that you can apologize, but that you deserve one too. I have a 7 year old daughter that still has her blankie. I'm 31 and still have my blankie. My 2 year old son has his blankie. There's nothing wrong at all for keeping a little personal comfort. However, because I've set the example to leave blankies in bed or in the very least, in the house while playing, they both do the same. Anytime they spend the night at grandma's, they have theirs with them. There are just ways to talk to them about it. I know a lot of people personally that have it in their head that kids don't understand a lot of what we're trying to get through to them... But they do. And if they don't understand what you're saying to them, they'll come right out and say it. I love that about kids. They will be honest about anything.
You did the right thing about sending him in the house for hitting.
What I would do is talk to him about it (even though he's probably completely over the situation). Tell him that you apologize for bringing up a sensitive subject with your friends, but that you deserve an apology for him hitting you too. Also, ASK him if it's an option to leave his blankie in the house while he plays. If he prefers not to leave it in the house, he's just not ready for it yet. Talk to him about how to respond to anger or frustration or being over tired... Let him know that he can talk to you and tell you those feelings. My daughter talks to me all the time about her thoughts and feelings. She knows that she can come to me no matter what. She'll tell me, "Mom, I'm mad at you..." And then we go into why and why I said or did whatever made her angry at me.
But you made the right decisions. And NO you didn't mess up big time. Messing up big time would be hitting him back. Or pointing and laughing at him for still having a blankie.