Is it possible to be a non practicing pagan?

I agree with Hellgha in the comments. Even if you can't do rites, I would recommend meditating or praying at least a bit. The gods may take offense if you are aware of them but won't make any effort to do basic rites.

Definitely not wrong, but I wouldn't recommend it.

I'm going to answer anyone here rlly, the Gods of the ancient religions of the IE traditions (indo-european) or almost all traditions troughout the world are prescribed as being perfect and divine. This means that they can exist whitin the cosmos whitout our praise. 

The philosopher Sallustius wrote about this issue in the 4th century. He asks, " How is belief in the impassivity and changelessness of the Gods reconciled with the idea that the Gods take joy in the virtuous, shun the wicked, and are angry with sinners while being appeased by worship?" He answers, "The Gods do not feel joy, or else they would be required to feel pain or anger (that is an emotion). Nor are they won by gifts; that would mean they were controlled by pleasure. Human conduct cannot affect the divine nature for good or for evil. The Gods are always good and help us; they never harm us." (This was based on the greco-roman tradition but it's used almost troughout all IE traditions)

But how does this affect us ? Well when we depart from the Gods (that means not praying, sacrificing nor devoting our time to them despite believing they are real) we become depressed, anxious, angry, lustful etc this could be seen a lot troughout the modern world. We pray to them because we need them but they exist whitout us. By doing these divine acts we cleanse ourselves from sins or the unwanted and get closer with the Divine and seek a union. 

Now, ofc the reason why one may not devote that often could be bc of trauma or other problems. And that is okay, the Gods are all the time patient and understanding. New age pagans have this idea that the Gods favoritize followers based on the offerings they give or that they can follow a path that sounds super absurd in theory such as "atheistic pagan" like OP mentions.

I'm not going to explain why these 2 do not work togheter. I think it's too hilarious for me to do so. Atheism is based on a religiousless life and creation. Gentilism (or how ppl today say it paganism) saw and still sees science/religion as 2 parts of the same coint. That should be enough to understand why such absurd combos do not work. 

Sure to be different in this world is a good thing. But how far can you go and where is the line ? Such "believers" will use old age traditions that their or others' ancenstors practiced as an aestheic for "fun" or bc it looks "cool". When in reality these represent the followers' whole lives from birth to death and by choosing such an ideology for your own fun you're appropriating the traditions. It's like you say for example that despite seeing ghosts you still don't believe in them.

Yes. This was very much the common person in antiquity, for example in Rome the only people who really gave offerings were the pontifex and the augurs, as well as senators and patricians. It was common in plebeians too, but plebeians without government roles werent really involved in the state religion insofar as just believing in it. Of course, all people under control of rome still at least were involved in festivals, but thats about it.