Hey !
1) No clue. Don't think you can, but I may be wrong.
2) Game no longer crashes under 1.94. Get it NOW !
3) Didn't understand the question.
4) Just create empty markers that you then "SetMarkerType" as you wish. To put them where you want, use the SetMarkerPos command. I'm not sure I grasp what you mean either when you say :
Or is it possible to handle markers like objects ?
5) Use the "RemoveEventHandler" or "RemoveAllEventHandlers" command.
Good luck, hope this helps.
Ig.