The typedef is just a shortcut version or macro of the full data type or structure etc., it should not make any difference to the compiled program.
The variables should be in RAM, unless it's an array or structure loaded with pre-defined "const" data as it is defined; that could be in program memory or auto-copied to data memory.
To see variable while single stepping, you may have to make them global rather than local. I've had problems when trying to debug using local variables used.