To be fair, they also made a number of fixes and improvements in the base code itself and like good Free Software citizens, contributed them back to the project. Those contributions are in the current 1.0RC2 release of FreeCAD. I think they were wanting to try the same play that launched RedHat back in the day. I appreciate their contributions and I'm sorry it didn't work out for them.

It may be worth going a little hotter. I do 245° (250° if a steel nozzle) and 5° hotter for the first layer. Part cooling no more than 20% except for bridging. I dry it it 60° with plenty of hot air flow.

I've been experimenting with that sort of thing. I've been experimenting with a slicer and g-code hacks to do inlays and other simple multi-color prints with just one swap per color. It looks like at least some printers could manage OP's print OK. One of my tests was a jack-o-lantern.