FFT 1.3 questions - Are mimes and calculators necessary?

I haven't played FFT since release, but am interested in doing a replay soon. I'm wondering if, provided I don't know the game inside and out and I don't want to read any strategy guides, the game is completable without using mimes and calculators? I have a bit of an aversion to these classes...

Also, am I correct in thinking the PS1 version probably has superior audio to the PSP version provided I play both through proper speakers? I'm leaning toward playing the PS1 version currently (I remember the script being fine, so that isn't a factor for me at the moment).

Calculators don't exist, and the game is plenty beatable without mimes.  It's OK to not know vanilla inside and out, because you're going to have to relearn everything anyway.

Ps1 and psp versions are 2 separate mods.  They were made by 2 different people, and thus do different things to the game.  I don't know which has better sound, but most mods are made on ps1 version so if you just get that version of the game, it means you can play other mods when you decide you're done with this one.

I'm very late in saying it, but thank you. I had no idea the patch removed calculators, but am relieved. I will play the PS1 version as I already own it and have confirmed the audio is superior.