Well I’m stumped. You write a long book mostly on the details of genetic engineering, saying we should use it to slowly change humans and their allied plants and animals, so that in 500 years we could launch them out to the cosmos, to arrive at other stars in a few thousand years.
I say, no, long before then artificial minds and life should have thoroughly replaced biology. A new kind of life, far more robust, able to grow far faster, able to travel out into space much sooner and faster, all made in factories out of stuff dug up in mines, and not at all based on biological cells, so that genetic engineering has little to offer them. If humans finally got to a new star under your plan, that star would have long since been well colonized by artificial life.