It varies from manufacturers. Some ESC allow reverse, or disabled reverse and allow breaks instead, or some combination (break for 5 seconds, then reverse).
for example HobbyKing has a bunch of programmers to make changing it easier. In most cases the same thing can be done with radio controls, although it generally is a bit more challenging.
I looked at your page a bit but did not see a reference to which speed control (ESC) you are going to use. If you have not chosen one yet, be aware that they usually come with instructions for programming reverse handling, timing etc.
Your assumptions about input seems reasonable, and is what I think you will find once you get going.