I have Shia freinds and they say they are syeds. The rest of the people are their ummah. The others should pay them respect as on the Day of Judgement they will be questioned. Many sufis and saints were Shia like as in Golra Sharif and Bari Sarkar and so on. So clarify the issue and oblige. If these saints were shias did they teach Shiism?
I can assure you that what you mentioned is not the belief of any learned Shia or Shia scholar. You can ask the same question from any learned Shia scholar and they will tell you that these are just imaginations resulted from lack of understanding of Shia and exaggeration.
The Prophet (pbuh) even warnd Fatima (ra-ha) to make sure she was doing well as a servant of God, since her relationship with the Prophet (pbuh) could not help her in the hereafter.
The Qur'an makes it very clear that the only thing that makes people better in the eyes of the Almighty is Taqwa (49:13).
These kinds of beliefs are similar to the beliefs of the era of ignorance (Jaheliyah).