Men are not known for their ability to communicate well. Put two screens and at least a couple of feet between you, and what used to be difficult to decode is now practically impossible.
You no longer need to fret over what his chatspeaking is saying, though. With a little bit of research and a whole lot of personal experience, I think I've translated at least part of his martian language.
He's interested in you and wants the two of you to talk. But he couldn't come up with a better transition from your non-conversation than "Hey." He's not very creative. But if you're interested, you should go ahead and respond.
He may or may not think what you've said is humorous, but he is not ready for the conversation to end. He's using "lol" as a substitute for a lack of response. He's hoping you'll figure out what to say next, so he doesn't have to.
3. "Can I come over?"
He's probably drunk and definitely looking to get naked. This text is his "Hail Mary" attempt to end up with somebody tonight. You are the target. If you're OK with a booty call, give him the go ahead. If not, don't bother responding.
He's trying to be cute. Don't merely assume he's trying to get into your pants. He wants you to think he's witty and charming so that, should you decide to go on a date with someone, you think of him. If that happens, then he'll probably try to get into your pants.
He's presenting the opportunity to have sex with him. He'll usually do this without any lead-up. He has decided to hedge his bets that you are up for it as well. The best response for this kind of text is to immediately shoot him down. Don't let him think there's a possibility of it working.
He actually means OK. He accepted whatever you said. Only girls put extra weight on OK, OK with a period, okay, k and OK without a period. To a guy, they all mean the same thing. He will use whichever one he prefers.
7. "Miss u"
He does miss you. But he doesn't mean it to have as much weight as you'll generally place on it. No, he isn't sobbing into a shrine of your hair and profile pictures. He would probably just like to get coffee sometime soon.
8. "Good morning :)"
He is definitely into you. It's hard enough for the poor guy to remember to brush his teeth and eat breakfast before he walks out the door, let alone text someone. You're special, so he made the effort. You should feel good about it (especially if there's a smiley).
He is responding because he understands that he should. He's actually not that interested in what's being said. You can try to refocus the conversation or choose to end it there. Maybe you'll get a "hey" in a few hours.