colleges accepting UPCAT

No, you can change your branch. You can only apply for relevant branch.

Your rank is not good to take admission in good private college. You can take admission in general college in your local area.

This Entrance Examination is open only to the candidates who have passed the qualifying examination from any institution located in U.P or whose parents are domicile of U.P, subject to the eligibility conditions given in this Information Brochure. If the candidate has passed qualifying examination from outside UP , he/she has to produce domicile certificate of his/her parents (Father or Mother only) at the time of verification of the document.

Of course, yes. Bansathali is India's largest girls' university. It is a very big and good university. Placement ratio is damn good here. Definitely, it will be better than any government college.

Click on the link given below and watch the video till end. https://youtu.be/hOlit6Un7l0
After watching the video follow the steps as described in the video.

https://www.shiksha.com/b-tech/resources/upsee-college-predictor
Please go to the college predictor link I am sharing here, to know about the college you can get.
Good luck.

Click on the link and watch the video till end. https://youtu.be/hOlit6Un7l0
After watching the video you will be able to find the list of colleges that you might get on your rank basis.

Yes, you can get, but you have to lock private colleges during the time of counseling.