You have mixed many things together in your message.
I pointed the error in your message not because I am member of one church or the other rather. Irrespective of our denomination, history remains as history. Though Christianity reached India in AD 52 we really don't have many historical documents with us to describe about the Christian life of that time. However, many historians already proved about the presence of 1st century Christianity in India. That means Christianity reached India even before it reached American and European Countries.
Contrary to this many people in India as well as western countries believe that it was westerners who brought Christianity in India. Similar is the case of Syrian Christians today ( I am talking about Christians in Syria not Syrian Christians in India). Today everyone around the world knows about Islamism in Middle East countries. But majority of them doesn't know about the indigenous Christian presence there. If someone asked about religion in Iraq, Syria, Lebanon, etc usually everyone will reply with Islam as Islam is the only known religion to the outside world. So, just as similar to Islam got opportunity to dominate middle east Christianity due to various political, economical and demographical reasons, western countries got opportunity to dominate India and people believe it was westerners who brought Christianity in India. Once an American asked me whether my parents also belong to Christian religion when I told him that I am a Christian. His impressions was that all Christians in India are recently converted. For your clarification, along with Vasco da Gama Jesuits reached India & with CMS missionaries Protestantism reached India.
As majority of people in India are Hindus, people who accepted Christianity also were from Hindu families mainly upper cast Hindus called Brahmins/ Namboodiris. And the local king always accepted them with high reverence. As the cast discrimination was existing among Hindus that time, obviously those upper caste Hindus who accepted Christianity were reluctant to accept lower cast people. Though foreign missionaries who reached India has created many troubles for local Christians, they have contributed positively also in some areas, like , removing cast discrimination, providing education, etc. Local people were not much educated that time and they used to worship in Syriac Language. (You can find influence of Syriac in local language Malayalam also.) After the arrival of missionaries, they have translated bible with participation of various local personalities like Kayamkulam Philipose Ramban.
Today we don't have much historical documents available about Christianity in India before 14th century. After the arrival of Portuguese it was a period of torturing for the local Christians as local Christians were worshiping in Syriac and Portuguese wanted to implement Latin faith. They destroyed all available documents to rewrite the local Christiana's history (that time Christians in Kerala was known as Nasranis; Nasranis means those who follow Jesus of Nazareth).
Anyway, in short, I would say though missionaries created many troubles for local Christians they also had contributed positively in certain other area. You can compare that life as similar to British India. British created many troubles for Indians in British India. But they have contributed positively in some other areas like Indian railways, etc.
In their worship local Christians accepted some local practice which is not known to missionaries. Local Christian leaders never discouraged this practice as they were not against the basic faith though one can't find a biblical reference for it. One such local tradition is minnu kettu (tying a thread with a small locket across the neck of the bride by bridegroom during marriage). They used to worship in Syriac as prayers were not translated into local language. In some parts of Kerala there was some influence of idol worship due to their Hindu heritage. Thus missionaries who reached Kerala termed entire local Christians as idol worshipers and started reformation. Those who accepted reformation changed faith. Those who were keen on original faith withstood it.
If there is any Christian group in Kerala who says they are Aronian or Levitus priest I would say they are wrong. Our priesthood is the continuation of priesthood of Jesus. However, new testament era is not complete without old testament era and vice versa. That means we can't separate one from the other. You can see many things which happened in New Testament era was already mentioned in Psalms and Isaiah. You can see in old testament how Araon was getting ordained by Moses. Similarly you can see how Apostles were laying hands on others before sending them for their work. In old testament priests used to sacrifice animals to please God. In New testament Jesus sacrificed himself and established Holy Qurbana to please God. None of these are not merely coincident but one incident can't stand without the other.
As similar to you I am also sad about fights between various Christian groups. This kind of problem is there in every Christian group today across the world. The only difference is that some are fighting inside the room others are fighting on the street. However, that is not an excuse to abandon right faith. Those who are fighting or doing injustice will be answerable but not others.
In first century, people accepted Apostles as the leaders of Christians. We can also find in bible that our Apostles were blessed with many spiritual gifts. They were called to their mission by our Lord while they were busy in their work like fishing. similarly becoming a priest is also a call. Everyone could not become a priest. And even if there are someone as priest who are not called for that job, they won't be able to perform their duty. Sometimes though they are called they don't perform their duty due to evil influence. That is why we see some bad news about some priests in newspaper and other media. So it is not the problem with the faith but it is the problem with individual. If someone assumed a wrong job for which they were not called they will come in news for wrong reason. I hope you are understanding.
Judgment is there for everyone. Apostles, bishops, priests and laymen have to undergo judgment day. Everyone will be answerable for their own action but not for others action. Why are you worried over that? You and I will be safe if we are doing our job properly for which we are called.
It depends on how you are attending Qurbana. There are two ways for attending Qurbana.
Watching Qurbana means you are watching it like a movie which is not going to help you.
Participating means you are becoming part of it. If you are becoming part of it, you will understand the difference. You will be able to experience it. You listen to it carefully and understand its meaning.
Today we have many options and many languages. This was not the case with our ancestors who had very limited options. The qurbana was mainly conducted in Syriac. If you ever get opportunity to listen to a qurbana in your mother tongue, please analyze its meaning.
Then you will understand that many of our self made personal prayers are blunders. Many people are not praying; they are making demands and comparisons.