This one is hard...?

Take Ian's kidney and give it to Emma, but this is not the doctor to deside but Ian relatives... isn't it?

I don't know if you're trying to suggest that maybe we should take Ian's kidney for Emma... but virtue of ethics would require us to let poor Ian's life run its course UNLESS the family took him off the machine.

Utilitarianism -- greatest good for the greatest number of people

Ian's in a terminal state of coma, so he won't know the difference -- no gain/loss of happiness.  Emma will have a substantial gain, therefore, you should take Ian's kidneys out.

That would also be the pragmatic approach.

Relativism and situationism refer to the absence of absolute moral rules.  It isn't generally good to take someone's kidneys without asking, but in this case (hence 'situationism') it is ok.

Use wikipedia, you can learn more than you'll ever want to know about those terms.

If I were young enough to learn a new career, or old enough to be close to retirement, I'd say to hell with the laws, and I would give the kidneys to the patient who needs them, Ian doesn't need them and his condition has no chance of improving, I would put him on permanent dialysis to circulate his blood and give his family a chance to say goodbye.

I would then leave the medical profession content in the knowledge that I had saved a life that otherwise would have been let to die.

Ian's family can decide to give up a kidney to save another persons life. It happens every single day. Just last week at the hospital I volunteer at, the family of a woman gave up one of her lungs to save another woman who had cancer. The woman in the coma will never come out of it, probably not anyway; so she'll never know the difference. Family input holds a lot of weight in decisions like this. However, if Ian's family refuses the transplant, there is nothing a doctor can do.

This is an ethical dilemma, NOT a moral one, therefore none of the theories you listed applies. If the law in your area keeps you from approaching the family and asking to donate, then there is nothing you can or should do. If the family declines, then you do nothing. If the family affirms and there is no legislation against it, then you may harvest a kidney (only one is needed).

pull the plug

Theory applied here is Ethics due the straight uniformity/regulation of the Med-care system.

Sorry, you could not solve this without specific criteria:

Blood type of patient.
Doctor with proficiency in Kidney Transplant.
A patient with insurance or someother way to cover the bill pre-surgery.

However, if all diagnostics agree that the only resolve is a transplant of the two forementioned patients by the one and only Dr. on the floor who can with none other avail, then so be it of the doctor.

I will answer in 7 ways

Don't play God, if she is meant to have the kidney then he will die in time.

Depends on the point of view

Ethically,  obviously whatever the rules say.

One could die, both could die, or both could live.

Donate the kidney.

Obvious

Giving up the kidney so both can live.