Good article, though the carciomeat seems a bit unnecessarily grim - cultured meat is getting close to being a real thing now, and to my understanding, they have not needed to defeat the bioregulation of cell growth. I would expect that such tissue would make very poor 'meat' due to the chaotic nature of cancer cells.
Also, I would add Designer Game creatures to the list. Related to the GE plants, we have GE animals now, and I expect the cosmic era would allow for even more strange and exotics beasts to eat.
If we are talking silly, then let your players put this on. It fuses permanently (maybe can be removed with a quest) and grants them some magic effect. As well the ability to be the subject of much curiosity and derision. Go to Comment
A very good vision on the 'perfect' semi-organic lifeform.
Probably the biggest potential downfall of this race is its inability to continue if the central infrastructure is somehow taken out of the picture. Unable to reproduce without it, tied psychologically to it, the centralized nature might be an impediment to it taking over. If the sun went crazy and EMP'd the hell out of the solar system, humanity might eventually recover. These guys would not.
A terrible teleportation incident makes inter-demihuman chimaera of all the PCs. Quoth Master Adams: 'I teleported home one night / with Ron and Sid and Meg / Ron stole Meg's heart away / and I got Sidney's leg.'