Another thing to consider is the sequence of events.

Has the person/character already chosen a career (Would have wanted you to) or are they making a choice right now (would want you to)?
Depending on the answer, the subjunctive (if she were alive today) might be the part that needs changing.

This one feels correct:
2.) If she were alive today, she would want you to become a doctor.
It feels correct because today is when the decision is being made in that sentence.

If the decision has already been made this would be more appropriate:
3.) If she had been alive, she would have wanted you to become a doctor.

The point is, her not being alive must line up temporally with the decision.

I have a similar dilemma: a question said as a statement, where the strength of the character is revealed through his tone. He is not looking for an answer and thus his tone drops at the end. If I write a question mark there, then the reader might read an upwards inflection and miss the subtle insight.

The question/statement is as follows:
'How about I settle that grumble in your belly and show you what the fuss is all about?'
or
'How about I settle that grumble in your belly and show you what the fuss is all about.'
As a reader, which one works to convey that he isn't going to take no for an answer?

Maybe I should just rephrase it to avoid confusion:
'Let's settle that grumble in your belly and show you what the fuss is all about.'
But damn it, why limit myself like that?

With 'Who knows', who knows which one is right. It can be expressed as a direct question, like a teacher asking 'who knows the answer to this?'. Or it could be said with sass, like the oracle in the Matrix when she is asked to clarify what Neo is waiting for, 'Your next life perhaps, who knows.' Her tone drops to imply she has no further insight for him.
'Who knows what the answer is.' feels like an alternative of 'I don't know.' or 'No one knows.' or 'I don't know who could possibly know that.'

If this is still confusing, you are not alone.
Don't worry, have a cookie and you'll feel better.