Project Pokedex - Buttons & Batteries

Hey all,

I wasn't sure if this is the right forum to post this, but here goes.

I'm trying to mod a Pokedex from the 90s to make it do cool stuff. I originally planned to dump all of the original electronics, but having opened the thing, I believe there's enough room in there to jam an Arduino Pro Mini and keep the existing electronics; if this allows me to keep the existing buttons working, that would be epic.
If not, I'm still curious on how I could get (at least some of) those buttons to interact with the Arduino.

So - I would appreciate some tips on whether or not it would be possible (for a n00b who has barely soldered before) to make use of the buttons on the device's front, or the batteries in it's rear.
I haven't been able to find any wire diagrams or specs of this toy, but I did take some pictures! Thumbnails link to full size.

Here are the buttons:

This is the board that interacts with the buttons (could I solder some stuff onto it to piggyback on the existing sensors?):

And this is the back of the board and the batteries - I have no idea how to get power from button cells, and it seems to me like this board needs one battery for the sensors to work, but the other one is labeled "backup battery" so I could probably use it:

Thanks in advance!