Hi Sahu,
1. Settlement can be done before or after TECO. You have provision to create the settlement rule at Release or at TECO. Certain companies needs to have the cost for monthly, so they have settlement rule created at release. Some clients wants to do settlement only after TECO to ensure order is completely costed.
It purely depends on clients business process, you can check with FI consultants, how they want to progress their month end.
2. and 3. You can use reports KOB1 or CJI3 to get the actuals posted, if you filter the KOAO business transaction in the report, which will correspond to settlement.
There are other S_ALR* reports, you can check those also.
Regards
Terence