CC asteroids have hydrogen, oxygen and carbon and with chemistry a bit like

https://www.dakotagas.com/

that is, CC asteroid contain “coal” more or less.

I don’t see a problem with drawing flowsheets for metals like iron, stones like silicon and even BTX chemicals to produce plastics. You cycle syngas and treat resulting H2O and CO2 as precious.

Now I was not thinking of a 500kg “seed” but a factory factory that is packed up in 100 ton loads that builds a sunshade factory by a process like building a ship inside a bottle except inside out.

I did worry about how you handle devolatization at the beginning, like it is precious and maybe even dangerous and it would be real nice to do it all at the beginning but you don’t have the storage tank factory online (thought a lot about storage tanks!)

The plan was to do all this in our solar system to sail sunshades to the Earth-Sun L1 point, the big questions I had was “how do you fix problems when it is hands-off that far away?” (physical twin in cislunar space for one thing!) vs “do you send people who you have to keep alive? can you bring them back? do they turn into Zeons?”

I have thought about the Drexler problem when it comes to Mars colonization and can’t think of a better answer than a synthetic biology platform based on bacteria and possibly yeast which can do versatile if not efficient chemical synthesis from syngas or photosynthesis. You still need flow chemistry, 3-d printing and some more methodologies but the project of “advanced manufacturing” that would enable a small settlement to achieve autakry seems achievable to me and would be essential for interplanetary colonization and helpful in case of forced degrowth.