B.Sc

B.Sc Botany is more of a practical subject. So, ideally, it should be done through a regular mode. While the MBBS degree is difficult to get and takes 6.5 years or so, you may look for alternative ones like BHMS, BAMS etc. or physiotherapy, pharmacy etc.

Yes, you can get admission in any college.

MBA is a good option for BSc student if he wants to change career stream and wants to become a generalist.

MSc in Chemistry will lead into teaching positions only. Industry Vacancies for MSc-Chemistry graduates are very limited. Rest people depend teaching profession after MSc. If you are focusing Teaching Profession, you may take MSc.
MBA help u to touch the top most positions in coporate. You can also turn into teaching field after MBA. Dont think MBA subjects are difficult for you. Even Language Graduates are passing MBA.
Tthink about both and take a right decision

Both BSc and BTech meets minimum educational requirement to appear for Civil Services Examination. Civil Services is one of the toughest examination of India. Very few lucky one makes it to elite services. I will recommend BTech over BSc for graduation because it provides better job opportunities. BTech will act as a stand by in case you can not make it to Civil Services. Also with BTech degree you can also appear for elite Engineering Services examination also.