The config files are different, the memory protection bits shouldn't make much difference but one uses the internal RC oscillator, the other uses the internal LP oscillator. these are quite different, to use the RC oscillator you need external time constant components to set the frequency, the LP oscillator is frequency trimmed and inside the PIC. This might acount for the program not running but I doubt it fully explains the file size differences.
The optimization levels are nothing to do with the source program or PIC settings, they set the methods used by the compiler to reduce code size or speed. I do not use Hitech compilers but I would guess the 'lite' has no optimization and the 'pro' has full optimization. The appeal of smaller faster code is what they use to make you buy the pro version.
Brian.