Hi ale ,
Yes, you should be able to execute your tests in BitBucket Pipelines using TestRunner command line
In Jenkins, were you using the ReadyAPI Plugin or using cli? If using the CLI, you would be using a very similar approach for BitBucket Pipelines.
And correct, a Floating License is recommended for running tests in CI/CD environment.
Regarding number of seats/licenses & pricing, I would recommend reaching out to the SmartBear team to discuss this further