Various messages, cannot find a solution

With my OwnCloud 10.9.1. there are some messages

1: oc01 — ImgBB
How do I find out which PlugIn/App is an Enterpriese? Because I do not need an Enterprise version
2: oc02 — ImgBB
What does the message mean?
3: oc03 — ImgBB
3a: “Transactional locking” I have looked at the documentation, but can’t figure out what needs to be changed.
3b: “We recommend activating the system cron” I have activated AJAX because it works fine for me. Cron does not work for me somehow
3c: “Some files did not pass the integrity check” There is a long list (Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.) . How can this be fixed?

Thanks for the tips