Since the police said that your arrest is not required and you were not arrested by police during investigation, after filing of charge sheet even if your formal arrest is shown by court you may be granted bail. File a bail application when you are produced in court.
The investigating officer forms his own subjective opinion on the evidence with which you may or may not agree. If you feel that the accused persons have been wrongly charge sheeted even though there is no evidence, you can file a discharge application in the trial court, or during trial you can show that there is no evidence.
Third question is already answered in the first para above.
Whether different sureties are required or not, may depend on the bail order (including amount of surety / bail bond) passed by court and also the solvency of the surety concerned. Wait for the court order and do as per directions of the court which passes bail order.
It is not possible to tell you without seeing the evidence as to whether you should go for discharge application before trial court (going to high court for quashing of charge sheet may not be preferable). Consult some local lawyer at your place about the evidence on record.
Yes, all accused persons (who have been charge sheeted) will have to remain present on all the dates when summoned, subject to exemption, if any, granted to any accused.
Read, for your last question: What are different stages in procedure followed in criminal cases?
Dr. Ashok Dhamija is a New Delhi based Supreme Court Advocate and author of law books. Read more about him by clicking here. List of his Forum Replies. List of his other articles. List of his Quora Answers. List of his YouTube Videos.