In answer to your questions below and also a couple of pointers.
A. We did this on a few projects in the Middle East with great success, but we well aware of the depth of the bedrock, so were confident of achieving 30M
B. On another project we used a Water Well rig to drill 30M peepholes that we then installed the conductor and base plate ready for the drilling rig, thuis avoiding fitting driving hammers etc to a drilling rig and having to carry out frequent drops checks in the derrick.
1. Go with 12M lengths to allow for any premature standup to allow easy cut off.
2. Use couplings, we used heavy wall Buttress connections.
3. use heavy wall if possible
4. The pipe supplier should be able to provide the parameters, https://www.ebicoilfield.com/drill-string/conductor-pipe-drive-pipe/
5. Ensure straight to start with and take time to monitor as can always nudge back straight with a D9 or the same crane using the drive Hammer