1.) Yeah, i would think so. but to accomplish that, we would need to invent a whole new sidepart in Biology, which i call DNA-Crossing
2.) While the inner Structure just need Bones, airfilled Korridors, a liquid(blood)system, Brains, (yes, more than 1 is needed if we go BIG) Nerves and a Gastrointestinal system, the Hull is where we face the tough Problems. It needs to withstand Radiation, Temparature changes between the Point off absolut Zero and, (well how hot get a exploding Star?), then we have ultra-fast moving Microobjects, and the List goes on.
An organig Spaceshiphull, that could face all these things, would be a Challenge. I would start wit a Fungus, that can hold a lot off Water. The Water would be needful, because it would transform a lot off ionizing Radiation into Heat, so we are safe and Warm inside the Ship. 671
Then i would teach the Fungus, per Genetic Enginiring, to get symbiotic with some Algeas for Oxygen, and Extremophile Bacterias from Hot Springs, the Antarctic, and coolingwaterbassins from Nuklear reactors, so it can perform even better, and Heal itself.
3.) Answerd (mostly) in last Point.
4.) That would be most likely Basic enginiring. Thrust would be just made with newer and stronger Rocket or Electric propulsers, like Magneto-plasma dynamics, and if we have more Oxygen then we need, we could use it as Fuel. Energy Production would be most likely a Fusion Reactor. We are now building Prototypes (Gen Zero) with ITER, and i think when we reach Gen 6 to 7 or later, we would have the expirience to use them safely on Space Ships.
For AG (artificial gravity), i am having an Idea. Since nowadays our understanding for Particles like Neutrons and Neutrinos is growing, i have thought of a Manipulation of these or others, to do our biding. In these Case specific, to create an Effect, that would be synonymous with an pressure Wave, that hits us constantly with 9.8 m/s.
5.) That Science Field is called Kybernetic, and it is an Ethical Mess, so i will not say anything about it 435