While granting visa to solo traveller and first time, one of the things looked at is age and marital status. This is to prevent immigration through tourist visa. Most filtration happens with age less than 30, single women without strong interests like real estate back in India even if they are salaried. You need a strong covering letter on why you want to visit and why you will come back - you have successful business here and family and estate in India.
1. Yes, business proof is needed.
2. You can add as many as savings, current account as proof to cover expenses. Please add real estate proofs also if you are in above bracket.
3. Yes, you can choose any city.
4. Don't confuse multiple entry and long term. Even for 30 days or 5 days opt for multiple entry and they will give. This is if you have to move out of Schengen area and come back.
What you are looking is long term. I recommend not to try for first time. Once your first trip is completed, next time try for long duration and ask in covering letter. They will oblige and give 1 or 2 years.
Regarding the country to apply for, in my experience Germany is smooth for tourist visa. But it varies depending on many factors.
