Arg I'm Mad!
Most of the screws on the Emaxx are either Phillips or Hex head.
If you are having a problem with these screws it must be you.
I have rebuilt my Emaxx a few times and NEVER had a problem. NOR have I seen different screws used to hold on the same part in the same location.
You need to calm down and take your time and use the right tools.
Any screws that have hex heads should have had the wrench included with the truck in the box. Unless you ripped open the box and tossed all that stuff out.
Either way it sounds like you are making a simple job very difficult through either lack of knowledge and/or experience with R/Cs.