Hi!
My name is Stefan and I’m a Sound Designer at Toontrack, so I will answer the questions that I know the answers to.
1.
The way that the graphics are done in EZD2 is not the same as in EZD1, therefore there can be differences in how the samples and articulations are being triggered when clicking the mouse in the GUI if you compare the two. The EZXs does however still contain the same amount of samples and react the same way to MIDI as before.
1a.
Superior Drummer has always used generic looking drums in the GUI. So the expected behaviour is that Americana and Jazz should have drums with the same colour, but with different sizes and positions (in Superior). Latin Percussion should have percussion drums.
1b
The presets in EZD are a new kind of presets that include both drum selection, effects and mixer bussing. To gain access to the kit presets that you could choose in the top left corner of EZD1, you need to go into the drum selection of any of the individual drums and to the right side of that window you have the old kit presets. If you want an EZX to sound the same as they did in EZD1, choose the EZD2 preset called Original Mix (or any of the EZD1 presets that are still included) and then choose any of the drum kits from the kit presets in the instrument selection window.
I hope this helps, let me know if I didn’t make sense 
Stefan Bränberg - Toontrack
Coder