Based on JCVI-syn3.0, they've added a few genes back to give better phenotypes, including slightly faster duplication time. Because the development cycle time is your God is also true in biology.
As of essential metabolism for a minimal cell (2019) it had only 91 genes of unknown function! So funny.
Bibliograpy:
The cool thing about parallel evolution is that it shows how complex phenotype can evolve from very different initial genetic conditions, highlighting the great power of evolution.
They are actually inheritable! But alleles are rare: www.ncbi.nlm.nih.gov/pmc/articles/PMC5559844