Success!
After I extracted exec.library 44.4 with RomSplit I added all the modules from BlizKick I needed to the rom image. The only one that failed was romfixes. It needs scsi.device in the image to be patches or Remus gives an error. So I added romfixes to the Kickflash program CoyoteFlash instead.
Only other problem was that I needed to patch the ram-handler from BB2 but this is mentioned in the Remus docs.
All is fine now; only gripe is that I can't start MOS anymore. This happens because the starting of MOS maps a custom rom to the maprom I guess. This is then replaced at reboot by the Kickflash and the machine hangs. After rebooting it just loads OS3.9 again. Is there a solution to this?