1 i dont know if i undurstend first question but i think the answer is no. You don't need to create image you can burn direct to CD.
2 You need to create ISOTrack and burn it with NeroDrive.BurnIsoAudioCD();
3 You have to burn multisessios
General what you shoul do for multisessios (for CDs)
1You should ask for a NeroDrive.CDInfo to see if the disc is empty or not (handle OnDoneCDInfo).
2If not empty, you should import a track using NeroDrive.ImportIsoTrack (handle OnDoneImport or OnDoneImport2).
3You should now create a NeroISOTrack object and add to it whatever folder hierarchy you want and optionally add the imported folder structure.
4Finally, you should call BurnIsoAudioCD.
For DVD is a litle diferent becouse you need virtual multisession.
For DVD multisession se this thread