Polytheism is the worship of or belief in multiple deities, which are usually assembled into a pantheon of gods and goddesses, along with their own religions and rituals.
Allah is The Absolute Just, Merciful and All Knowing. He never punishes those who do not know the religion of Islam. He said in Quran : We never punish any one till We send a messenger وما كنا معذبين حتى نبعث رسولا (Sura 17, verse 15).
Those who did not know the message if Islam and died on that ignorance will be given a full chance in the Day of Judgement to know then will be given full option to think and decide then respond.
The Justice and Mercy of Allah will never allow punishing any one before providing him full chance of knowing and deciding with his free will.
Allah (SWT) created all His creatures for showering on them His countless bounties and unlimited Mercy. We read in Qur'an: (Except those on whom Your Lord Has bestowed His Mercy, and for that He did create them). (Sura 11, verse 119).
Allah never created people to send them to hellfire, except those insist on criminal acts and continue committing injustice and die on such criminal acts.
Allah, The Most Merciful, The Most Compassionate gives every human being thousands and thousands of chances to believe in thr Truth and do good then enter the Paradise.
Allah (SWT) Has promised every one who believes in Him as The One God to go to Paradise as the Prophet Muhammad (SAWA) said: Paradise is the ultimate place for all believers in Allah الجنة للموحدين.
It is not correct the think majority of people since the time of Adam were atheists or non believers. Majority of human beings are believing in The One God which is part of the instinct knowledge even if the cultures and titles are different.
'The Mercy of Allah is much more greater than what we think and He will deal with His creatures with His great Mercy except the enemies of Allah.
Polytheism شرك is to worship with Allah some one or something else. Those who did polytheism in the past then left it and became Muslims will be forgiven because they have left polytheism, but those who insisted on polytheism and died with it, will not be forgiven as you read in (Quran 4:48).
Allah (SWT),The Most Merciful, The Most Just, knows who is entitled to be in the Hellfire. We are read in Quran that the enemies of Allah will remain in the Hellfire as they were insisting on doing wrong forever.
We should not waste our time in searching what will happen to others, rather trying our best to save ourselves from bad deeds and sincerely doing good in faith and practice to be with the Righteous in the Paradise.
Hadeeth says: The Paradise in the ultimate place of the believers in Allah الجنة للموحدين
If you repeated the wrong words of others with out intention of its meanings of Shirk, you are not a Mushrik. Your faith is what is in your heart. Still you need to repeat Estighfaar for saying something wrong.
Thank you for your question. It is polytheism if the person sees Imam Ali (as) as an independent source of help from God.
May you always be successful
No Forms nor manifestations of God :
Islam is the pure message from the One Creator Allah (SWT) for all
people to make them know that there is no god but Allah (SWT) and no
one has the right to suggest any form or manifestation for God.
Allah (SWT) does not need people to suggest forms or manifestations
for Him. In fact the Holy Qur’an is very clear against these so called
forms and manifestations because it leads to polytheism. Allah (SWT)
ordered people to worship him without their imagination or forms or
manifestations and those who create what they claim to be forms or
manifestations are away from Allah (SWT). When they are being told to
worship Allah (SWT) only and not others, they say : “We in fact
worship them to get proximity to Allah (SWT) (ما نعبدهم الا ليقربونا الى الله زلفى).
(Sura 39, Verse 3)
Islam being the final and ever-lasting message from Allah (SWT) does
not accept any claim of any forms or manifestations of God and deals with it
as a type of Shirk (Polytheism) which is the most dangerous major sin.
Thank you for your question. The problem with such religions is their specification of certain manifestations of God and then what their beliefs about those manifestations are. In Islamic mysticism the issue of manifestation has been discussed at length and an absolute lower boundary to understand manifestation is that it should not result in idolatry, which is exactly what the specification of forms to which people direct worship is. Monotheism is not only the specification of one God, but the unity and unlimited nature of God and His being above any material being.
May you always be successful.
The Qur'an presents the theological argument that, if there were multiple gods responsible for creation, there would be fighting or differences of opinion on how to manage creation, and this would result in chaos or destruction (or at least a lack of consistency in the universe). However, we see that everything around us runs smoothly and in a unified manner - for instance, the laws of physics do not change from place to place - and this suggests that there is only one intelligence responsible.