CBSE 12th

After being a commerce graduate you'll mostly get jobs in the corporate sectors. There, after 1-2 years of experience, you can take up an MBA degree to get better prospects. Hope this helps.

If you have low percentage in PCM, you try to perform well in the entrance examinations for a good college. They won't give any weightage for your 12th marks.
All the best.

Yes, you can definitely apply for government jobs. But for the pharma industry, other than the job of MR, they mostly look for B.Pharma graduates. To be more clear, they prefer B.Pharma graduates over other candidates.

Use the Digilocker app, enter your Aadhar card details and retrieve Digilocker-verified marksheets, so you can use in counselling and admission procedure, same time apply for duplicate marksheet on CBSE website with procedure. You will get duplicate marksheet.
Don't worry.

First of all, for getting admission in NIT, you should have 75% as minimum marks. You need 5% more for eligibility to get NIT.

You can go for UPSC preparation. Most of the syllabus of UPSC is from humanities.

No (as per the last year's statistics). But many seats were left empty last year, so you may try to get a seat if you're lucky enough.

Since you are an aspirant of B.Tech in agriculture, you might not need coaching that much. Still, if you are planning to go to Kota then you might perform well and can also go for more good branches in many good colleges. But it's good that you have your goal clear. Work accordingly. Keep your spirit high.
All the best.

Yes, you can easily get admission in the 1st round.