It depends which angle you're looking at it from. Is Paganism compatible with Christianity? is, to be frank, a hopelessly vague question.
Paganism is a very broad category. Most Pagans would accept Jesus as a deity. A few might include him in the their personal Pantheon. Most wouldn't. It is certainly possible, though, for a Pagan to do reverence to Jesus within a Pagan context. From that perspective, yes, they are compatible.
Christianity is also a broad category. Many Christian traditions are unashamedly borrowed from Pagan sources. There are aspects of Easter which are drawn from a spring fertility festival, and Christmas and Halowe'en also show signs of Pagan influence. Various customs and rituals (such as churches being oriented toward the sunrise) may also have a Pagan origin. Does that mean that Paganism is "compatible with" Christianity? Well, it certainly means that some traditions are compatible.
Really, the problem here is that your question is very poorly defined. There's no good clue as to what you're actually asking. I've answered two questions. I suspect that neither is the question you're actually asking.
Let's move on. It's not just traditions and rituals which are derived from Pagan sources. Some Christian beliefs are, too. As an example, the Gospel writers Matthew and Luke developed a story that Jesus was born of a virgin, with accompanying signs and wonders. Why did they tell this tale? Because it was, at the time, part of the standard mythos of a hero. Mithras was born of a virgin. Julius Caesar was born of a virgin. In fact, here's a list I nabbed from somewhere:
Julius Caesar, Augustus, Aristomenes, Alexander the Great, Plato, Cyrus, the elder Scipio, some of the Egyptian Pharaohs, the Buddha, Hermes, Mithra, Attis-Adonis, Hercules, Cybele, Demeter, Leo, and Vulcan.
Actual Christian beliefs taken from Pagan sources are, of course, a more contentious matter, since many Christians will disagree about the origins of these stories. Looking at religion at the outside, as a series of memes borrowed and reshuffled, this seems pretty clear. We borrow beliefs from the broader society in which we find ourselves. That's how these things work. It's how we all work. We could not be otherwise and yet be human. The Trinity doctrine, for example, is frankly weird, and there's vanishingly little evidence that it was part of Christianity in the first century. And yet now the vast majority of Christians accept it and call it a defining part of their faith. Again, it was borrowed.
Does that make Christianity "compatible" with Paganism? Well, the word compatible remains hopelessly ill-defined in this context, so I can't say. I suspect not. A mere convergence of belief in certain specific areas, however those beliefs are derived, is not the same as "compatibility", by most definitions.
Let me put that another way. Christians have a religious framework which prioritises belief over practice, which presents a hierarchical view of the universe, and which is history oriented. Pagans, by and large, have a religious framework which prioritises practice over belief*, which has a far less hierarchical view of the universe, and which is more cyclically oriented. They are very very different. If in certain specific areas, they have a couple of beliefs or traditions in common, they are no less different overall. I don't know what definition of compatible you're using, but by most definitions, Paganism and Christianity are incompatible.
* Pagans with very different beliefs can participate in the same rituals; Pagans with very similar beliefs may have incompatible rituals.