Can Christians, Muslims or Jews worship or pray to pagan gods?

Not while remaining faithful to their religion. A core tenant of all three faiths you named is that their God (which are all different interpretations of the same god) is the ONLY god and you cannot recognize any other god.

Of course, there have always been varying interpretations of each faith. Christianity, especially, has lent itself to syncretism quite well. There have been (and still are) many cultures where the people would identify themselves as Christian, but see no contradiction in also recognizing aspects of other faiths, including sometimes gods (although they might call them some other word).

If you're following any of the major, world-recognized denominations of Christianity, Judaism, or Islam (eg Catholicism, Protestantism, Sunni Islam, Orthodox Judaism, Shia Islam, etc) then, no, you cannot worship pagan gods. But there are smaller versions of each religion which do.

You are right but I'd like to point out that you could argue that the holy trinity is polytheistic, or like LDS believe this universe's god is just one of many gods. But you are correct for the most part I just wanted to mention that
- At one time, the Church did indeed consider the Trinity idolatry and heretical.
- Well, there are a hell of a lot of Christians, Jews, and Muslims alive right now who aren't actively trying to kill each other. Mostly, they just let others go about living their lives. It's only the radical fundamentalists who try to kill others.
- The ones politicians keep riled up will.

They can do whatever they wish, they were given free will. Should their so-called god not like, it will strike them down or something.

I think mainly it's that deities allow us to suffer the consequences of our own in/actions until we learn the lesson at hand. It's unfortunate that's how it continues to be expressed, since religions began conceptualization.

Can a soccer player hold a soccer ball in his hands?

Yes under some conditions
- Same answer.

https://en.wikipedia.org/wiki/Thou_shalt_have_no_other_gods_before_me

I love how that part admits that there are other gods.
- "covenant" here, to my understanding, means marriage. Abram choose to be spiritually wedded to the Caanite desert/warrior/storm god. El was a peaceful god. 72 recognized names of God, afaict, but I be confusing that with hermetic kabbalah (Christian mysticism). Each name recognizes different aspects. And gnosticism is something entirely different.
Maybe the Jewish faith has kept to that but Christians have a long tradition of practicing syncretism and priests were happy just to get a Danish king to say "Hail Odin the all father and Freyr's might and uh... also the Christian God I guess."
- There's plenty of references in the OT to Jews doing the same thing.
  And European Christianity chased out worship of anyone save the God of Abraham rather violently after a generation or two.
Jewish law doesn't apply to gentiles, for good or ill.,
"Before."
Now the mystic branches of these religions have a different interpretation, to lesser and greater degrees. The fanatics in each would kill them all.
- Yes, I think as a pure theological question, historical thought has been a bit complicated. So I linked to the Wikipedia article that hopefully goes into it a bit. I admit to not having read the Wikipedia article carefully. This isn't my area at all.

Everyone can pray to what or whomever they like.

While it's a core belief of Abrahamic monotheist that there is no god but Gods practically speaking some people kept some traditionul/pagan belief. I think obviously about some Africans doing their own mix, but even in Europe, tons of Pagan belief stay around, stuff like knocking on woodor having a Christmas tree, let alone various form of witchcraft which are also illegal for Christians but quite common, no matter whether it's an old man reading runes or a teen girl praying the moon because it looks cool on TikTok

https://m.youtube.com/watch?v=z-GGIVKe9Cs
Text version: https://archive.org/stream/the-star-lore-of-babylon/The%20Star%20Lore%20of%20Babylon_djvu.txt
This gentleman from yesteryear spoke about that.

This really depends on what you mean by "pray."

Sincerely worship and praise a pagan godhead as if they were responsible for the deeds Scripture attributes to God? No. It's as bad as lying in court, stealing, or killing someone.

Falsely go through the motions of pagan prayer, such as in a game, as an actor, or under threat of death? Usually. Some are sticklers, but most are OK with leaving cookies for Santa.

Sincerely giving praise or worship to a being other than God, for things asserted as being done in God's service or things not done by Her? It depends. Some may be hard no, some may be open yes.

There are something like 3 billion nominal followers of the God of Abraham alive today. With such a large population, it'd be hard to find a statement that they all agree on, including "water is wet".

Ex-Catholic here, standard response where I'm from would be "No, our God is the only god and trying to contact any spirits beside the Holy Spirit just opens you up to all the evil out there".

My understanding is that Abrahamic religions are universally monotheistic and have been since the Babylonian Exile got rid of the henotheistic aspect of Yahwism. Expect to get a lot of pretty convoluted reasoning if you ask a Catholic whether having three persons in the trinity is the same thing as polytheism.

Yes. Do whatever the fuck you want.

You can do whatever you want but in most cultures that isn’t allowed. Depending on how you define pagan gods that is allowed somewhat in east Asia through Shinto deities, Confucian, and ancestors.

Should be the same for Christians and Jews, but for Muslims the answer is absolutely not.