The Christians do not even have their original scriptures to begin with. Their Church has conceded the intellectual fight with the atheists and evolution is a part of their doctrine now. So of course, Christianity is far from the truth.
In Shia'ism, there are some conditions to fulfill to be a subset of Sunnis. Otherwise there can be implications of Kufr in those sects.
O Allah, I take refuge in You from anxiety and sorrow, weakness and laziness, miserliness and cowardice, the burden of debts and being overpowered by men.
I know Christian religion is full of wrong stuff, but I mean is that when you want to study a religious group, it<s better to not it from sources that can be biased. If a Westerner wants to study Islam, he will have to read the Qur'an and hadith by himself, he can't rely on what non-Muslim websites say.
Sahih Muslim, Bk 31, Number 6117:
Allah's Messenger (SAWAWS) as saying: If the din were at the Pleiades, even then a personfrom Persia would have taken hold of it, or one amongst the Persian descent would have surely found it.
Anyways, we cannot see what is in the hearts of Shias, BUT we can see what is in their books regarding the Sunnis. Here you go:
Why do you sunnis think shia's are non-muslims?
Answer: Because Shiism is an attack on finality of Prophethood, Shiism rejects Finality of Prophethood.
Do Shias believe in Finality of Prophethood?
Had there been a separate Shia system of belief, why should Imam Abu hanifah & Malik went to Imam Jafar Sadiq in the first place!?
Imam Abu Hanifah studied under the father of Imam Jafar Sadiq too - Imam Muhammad Baqir. A little common sense and a bit of logic would cure the misconceptions.
P.S. You say Imam Abu Hanifah 'backstabbed' his teacher!? Abu Hanifah spoke of Imam Jafar Sadiq as 'the most brilliant mind in the whole world'.