Colleges in Kanpur

No both are different colleges in same campus. There is no difference in academics and placements.
The ratio of placements is combined with both PSIT and PSITCOE.
Every student of any college in the campus is treated same. PSIT is a group of 4 colleges and PSITCOE is one of them.

This branch has good scope.
Refer the following link:
https://www.shiksha.com/college/bhabha-institute-of-technology-Kanpur-37486/reviews

No, that can't happen as they are different subjects.

I think it is an average rank so it's not confirmed that your admission is possible or not.

The university has set up a full-fledged directorate of placement, which is a unique feature of the university and imparts job-oriented professional education in the fields of Agriculture, Horticulture, Forestry, Home Science and Agricultural Engineering.
Top recruiters -
Kanpur Chemicals Agencies
Dhampur Sugar Mills Ltd.
Agri Net Solutions Ltd
Pro-Agro Seed Company Ltd.
U.P. Diversified Agriculture Support Project
ITC Limited
BAIF Institute for Rural Development
U.P. Seeds and Tarai Dev. Corporation Ltd
Mastermind Classes Pvt. Ltd
Maple Orgtech (India) Pvt. Ltd

*You need to appear in UPSEE exam and have to secure good rank or you can get admission through JEE Main. *Another way to getting admission in HBTI through NRI quota, Kashmir migrants etc. And if you are Diploma holder, then you can get admission in direct 2nd year. It is called lateral entry. This process is being also through UPSEE exam.

CSE is the best branch for you because at this time, private institutions are not able to give good placements for the core branches.