Would that include creating Martian-type humans that enjoy the planet, the razor-sharp sands, and the isolation? The planet, or an equivalent domain of colonization, may be lucrative and good for humanity at large, but actually being able to work there turns out to be uncomfortable, disgusting, or tortuous for standard humans.

That brings up the Brave New World issue of castes forming, or niches that function like castes. Depending on the intelligence and minds of the created, you would have a blend of systemic inequality, domestication, and dystopian slavery. I don't think it's right to gamble lives and quality-of-life with those stakes. Not that every settlement will see it that way, especially when their own children aren't adapted to their proud colony or dingy undercity or wherever.

How about sapient machines below human level then? That category gets very blurry depending on what kinds of consciousness and intelligence are involved. And if a regional sewer inspector needs to be able to make conscious decisions, it doesn't matter if they their emotions run on silicon or biomechanical or meaty cells. Many drones will become more biomechanical looking but I could also imagine some with animal-level consciousness for enhancing their general intelligence or for improving social cohesion with humans. Whatever the ethics of engineering working dogs and therapy animals, they're still good dogs that deserve headpats.

Creating nature is a scarier thought. If a lion is made for a space wildlife preserve, and the environment is allowed to be naturally dangerous, that lion may will have low pleasure despite enjoying the "whee I'm a lion" part Creating nature like most bioforming is creating a self-sustaining process that typically involves creatures even as large as insects experiencing pain-like signals, and larger ones clearly capable of being confused by pain, inquisitiveness, and even sadness. Factory farming may be worse than that.

Then there's the freedom, as in a breadth of things to be and experience, and compensation. Lions have a different concept of freedom than most people, and may be psychologically unable to quit doing some pleasurable thing. People are born into farming families, they can ideally can move away if they want, but realistically many folks will have career regret even when they love their job or life. Our deal with any creation must be far more generous than the oversimplification of freedom that leads to (paraphrasing) "don't like your job, quitting is your freedom, so long as you obey all the contracts and don't blame anyone else when you suffer or die while being unemployed". It's a step further to make a purpose-designed species which will have a consistent proportion electing to quit their role, maybe 0/100. Material conditions should permit a being to quit or change, and it should be psychologically feasible or even expected to eventually do so. I'd want heritage to not be mentally weighted more than independently seeking to grow and expand unexpected aspects of wellbeing.

With immortals maximizing quality of life, the moral calculus may be that it's fine to create all sorts of beings to fill vacancies in unpopular "jobs", so long as they live a much longer free and happy life than their not-mandatory job. If a being happily does a designated task like a drone, or was a pet, and has the enough intelligence that it could be taught the concept of uplift, I'd want them to have the choice for retirement or quitting to be carefully uplifted into a unique and independent-minded person. Instead of going through infancy, an engineered species may have been purpose-built drones before they matured into diverse citizens.

So it varies but I probably won't object so long as all beings involved experience a lot of social mobility and self-invention. Creating happy and sociable drones let alone ecosystems may be difficult to square with animal rights predicated on similarities in human and animal minds and wellbeing.