Rafts:
Doesn't Matter
Supports:
Yes
Infill:
Needed on some parts.
Notes:
Please not a lot of this is guesswork as I do not have a multi material printer and have been unable to test it.
To print.
Using Cura as an example
Load parts into your slicer and set their materials.
Join the parts, they should align to their correct placement then scale them to whatever you want.
If I have done this right I believe it is possible to print it all at once with 4 materials, 3 colours and a dissolvable support.
I would suggest at least 150% scaling as some parts are delicate.