Engineering

No, it totally depends on your interest as there are many career opportunities depending on your knowledge in every course. And doing BA after your diploma is good . You have many opportunities after doing BA so there is lot of things to do in your field do you can go for this.
Good luck.

If your interest is in agriculture then you can do B.Sc in agriculture because this is also a good option. Else, you can join CSE but I think you should go with your interest.

Yes, outside students can apply. But you have to give either JEE or GUJCET exam to take admission in here because admission to BE is done on the basis of rank secured in Gujarat Common Entrance Test GUJCET conducted by Gujarat Secondary and Higher Secondary Education Board (GSHSEB) or Joint Entrance

Scholarships are based on your boards and Mains marks both.
Firstly, you are divided into 3 categories according to your board's marks.
1. 95% and above
2. 90-95%
3.85-90%
Students are listed out according to their JEE Mains score.
In every category, the number of students vary and hence scholarships vary

Hello,
I hope you are doing well. You can check the list of college including NITs and IIITs, you can get according to your marks and rank here. Use Shiksha JEE College Predictor:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=cconnect&utm_medium=CR_JEECP&utm_campaign

42 marks in JEE Mains are very low if you belong to general category specially. Because with these marks, you won't be able to get any government college in your state. Instead you can try for state college counselling happening every year where you can get college based on your state rank and JEE m

Hello,
Hope you are doing well. You can check the list of colleges including NIT and IIITs which you can get according to your marks and rank. Use Shiksha JEE college predictor:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=cconnect&utm_medium=CR_JEECP&utm_campaign=7

Check whether you can get or not
Go through the official link of shiksha.com
https://www.shiksha.com
Here you can predict college on the basis of your rank.
In predictor , Check for the AEEE , It will give detail about cut offs rank of the same exam. So that you will get notified.
Thanks