Hi and thank you for your interest in AmiKit X.
A) At the moment there is no Vampirized version of AmiKit X. We're still waiting for Vampire 1200 so we can make a special version for this piece of hardware. (There is only AKReal9 - an unofficial conversion of AmiKit 8 for real Amiga - which you are probably using now.).
B) In AmiKit X there is a button which switches to MUI3.8 and back easily. In older AmiKit versions you probably need to uninstall MUI5 and install MUI3.8 instead.
C) Again, in AmiKit X there is a single button for it. In older versions there might be a button too (check MorpheuZ program), or simply check startup-sequence. LoadDB command loads DOPus, LoadWB command loads Workbench. If there is LoadWB and your AmiKit still loads DOpus, then copy original LoadWB command to AmiKit:C folder.