B.A English

Dear,
With this percentage you can apply for these options:
Ambedkar University
Jamia Millia Islamia
Amity University
Apeejay satya University
You may try for Mumbai University or BHU as well.

First of all, Mumbai University does not offer BA honors in English. As far as national reputation concern, u fortunately there isn't any colleges in Mumbai except St Xavier's. You may look other as follows:
1. Mithibai College, it has a department of English
2. Ruia College
3. St Andrew's College
4. Wilson College

Yes, you can pursue MBA after completing UG in any stream.

You can go for certification programmes wherein you require only 10+2 marks.

No, you can't take economics, but you can take English in BA. You are not eligible for economics, because for that you must have math or economics at 10+2 level.