Which Linux live distro coming with OpenShot and/or Kdenlive is there and would you suggest me to try? I need to very occasionally use them and I don't want to install them by the moment.
Thanks in advance for your advices.
I think you actually listed the majority of the distros shipping
Kdenlive. I'm afraid there might be performance issues on live systems when it comes to video processing and encoding. To overcome these sorts of problem you probably might want to use a well-supported distro with a good drivers database, such as Ubuntu Studio 17.04, which includes both OpenShot and Kdenlive out of the box:
Keep in mind though that right now Ubuntu as a project undergoes serious changes, shifting its focus from the desktop distros to the cloud-based/server-side solutions, which means that Ubuntu Studio might not be the best Linux-based solution for the artists in the future.