We have one instance of SuiteCRM / kReporter currently in use. we will be creating an instance for two other entities. Can we copy the the reports in the original instance to the other instances?
Yes. Just export kreports table.
Export also table kreportgroupings if groupings are in use and other instances contain same grouoing data.
Be aware that reports might not work if data structure in other instances is different.
Example: you report on additional field in Opportunities in your original instance. If this field does not exist in other instances, report will break.