So I think there’s some equivocation on “Jesus’ followers.” There were the original disciples, who fled Jerusalem after his arrest. They probably had at least a vague sense of what the Romans did when they crucified people, although they may not have known all of the details. They fled Jerusalem and at least one of them later had visions of Jesus. They start thinking about what these visions meant. They start thinking, Jesus lives on in some way.. he’s been raised from the dead. God must have resurrected him. God must have shown him his favor. That must have meant that God approved of what he was saying/doing. And maybe it means that the the end of the world / the general resurrection (that Jesus preached?) is at hand. I don’t think these people knew what happened to his body immediately after the fact. He was dead. What did it matter? Only later when a few of them had those visions did it start to dawn on them that Jesus must have been really special.. either God had raised him from the dead or he had been something not fully human all along. 

The other sense in which you’re using “Jesus’ followers” pertains to the people who were telling the stories about his burial on the third day in a tomb. The tomb part comes much later. It doesn’t appear in writing until 40 years after the fact in Mark. You’re right that it’s very interesting that Paul indicates that he was buried. I assume that Paul simply wants to emphasize that he was really dead and he was really raised, in accordance with certain prophetic traditions that the early christians want to claim apply to Jesus. Note that Paul says nothing about a tomb or about who buried Jesus or where. It’s also very interesting, this tradition in Acts you point out where it is suggested that Jesus’ Jewish opponents – the ones who insisted that Pilate crucify him – bury him. At least it says “they” took him down and laid him in a tomb. It could mean that early Christians didn’t quite have their story straight about who buried him. But actually I’m not sure there’s any inconsistency since according to the tradition, it was this Joseph of Arimathea guy, supposedly a member of the Sanhedrin, who buried him. But the author of Luke..     see this is interesting..  the author of Luke and Acts wants to say

The Sanhedrin/the Jews handed Jesus over to be crucified

Joseph of Arimathea was a member of the Sanhedrin

Joseph of Arimathea dissented from the consensus that Jesus had to be executed. 

“And though they found no ground for a death sentence, they asked Pilate to have Him executed. When they had carried out all that was written about Him, they took him down from the tree and laid Him in a tomb. But God raised him from the dead…” 

What is going on here? Who is they? Is it the Sanhedrin/the Jews? Why would the Jews who just had him crucified do that? Is it that Joseph of Arimathea is included in they? That’s probably it. Probably the author is being a bit vague with his theys. Others seem to take this to mean that the author of Luke-Acts is possibly letting slip a different version of who took possession of Jesus’ body and why. 

I also agree that it’s not quite accurate or fair to say that it’s Ehrman’s theory that Jesus was left on the cross for the wild animals. It is something that Ehrman brings up in his books and lectures. I’ve read John Dominic Crossan bring it up more directly, particularly the suggestion that maybe Jesus’ body was eaten by wild dogs.