1. The IO will function i his own style and you cannot do anything about it becasue he may put blame on his work pressure and escape the questions.
1a. Unless there is a complaint agaisnt them they cannot be included in the FIR, the IO has to conduct the investigation properly and give his report about their involvement after which the court may pass orders to implead them also in the case.
1b. Your letter may not entertained by them especially when the matter is taking a legal shape.
1c. The bank will not yield to your pressures.
2. Actually you can withdraw the AB application from high court and apply for bail in the trial court itself since the police have not filed the charge sheet within the stipulated time.
3. You can file an application under RTI to the income tax department and get their reply in this regard otherwise wait for the trial to begin after which you can file a petition before court seeking direction to the income tax department to produce the desired document.
4. The IO may refuse to divulge the details of investigation during the period of investigation and he may even refuse to furnish the information through RTI act also during the pendency of investigation.
5. Without the beginning of trial your lawyer cannot file any such petition before the court.
6. If the injunction application has been dismissed by the trial court then you may have to file a revision before high court and not that you can file an injunction application again before high court.