Just a small update.
I'm placing and routing the ASIC card. And adding component values in the schematic.
I decided to use buffers for the datalines, just like in the other designs.
I picked this double schmitt trigger part from NXP 74LVC2G17GV, not to expensive, decent specs.
Also for the reset of the ASIC I'll use the STM6780TWB6F voltage monitor from ST. It's cheap, does what it needs to and can be reused for the Controller board.
The original uses an RC delay on the reset, I don't like it personally, not reliable enough, eventhough it would and does work.