The pandora could work as "pokedex" and you capture your monsters on sdcard. Dependant on the size of the cards you collect or buy ingame, you can store more or less monsters on one, while you can carry around as much as you like, you can only use the ones in a battle, that are stored in one of the two sdslots in the Pandora.
I thought of something similar, not quite sure how it'd work out practically, it'd basically just be like saving the game on each SD card.
Will there be evolutions?
You could even change the evolution system a little.
Only a few sterting monsters but with different ways to evolve.
This might be more complicater to make than the original Pokemon-system.
Yes. Primarily it will follow a level based evolution path. However, I plan some items that will allow alternative evolutions to occur.
I'm not quite sure how Pokemon works out stat upgrades, but my approach will be "experience based". Basically, if your monster has two attacks "Punch" and "Quick Attack", quick attack obviously having a higher speed, if you constantly use Quick Attack, the speed attribute on your monster will increase more than the other stats at level up time.
I could also use these stats to drive evolution chains. ie. Say if you start out with a mouse type creature. If you do a lot of fast attacks, it evolves into some speed based creature, but if it does a lot of defensive moves, it evolves into more of a "tanking" creature.
That last bit is a new idea and hasn't been fleshed out yet, but possible
Edit: I might look on this in making evolution chains longer, so reducing the need to think up tons of different creatures that are effectively the same, but giving a nice spread