You only need four things:

1. Immune system compatibility. This is trivial. In lab you can just keep mother on immunosuppresants. Done.

2. Compatible size and pregnancy time.. Again, this is easy, as you would probably use species of similar birth size & time in the first place.

3. Good proportion of substances in umbilical cord. This can be fixed by IV if needed.

4. Implantation of the egg. This is a tricky part. You need to be careful when setting up genes for this process. Preferably rip them whole from mother 0 species and call it a day.

Probably there is more to it, but our science is at single cell synthetic life now, and we are yet to see what will happen.

You only need four things:

1. Immune system compatibility. This is trivial. In lab you can just keep mother on immunosuppresants. Done.

2. Compatible size and pregnancy time.. Again, this is easy, as you would probably use species of similar birth size & time in the first place.

3. Good proportion of substances in umbilical cord. This can be fixed by IV if needed.

4. Implantation of the egg. This is a tricky part. You need to be careful when setting up genes for this process. Preferably rip them whole from mother 0 species and call it a day.

Alternatively, go with eggs. If your organism does not need to give live birth, it would not need a mother. This is a route I'd prefer.

Probably there is more to it, but our science is at single cell synthetic life now, and we are yet to see what will happen.