Subjuntivo

[zuma022]

I can't figure out this part of my homework and I'm hoping someone can help.
I have two sentences and need to explain the difference in meaning and say which one has a more positive attitude.

Me gustaría encontrar a una persona a la que le interese viajar.
Me gustaría encontrar a una persona a la que le interesara viajar.

I think the first one means, you know somebody like that is out there, but you have not met him or her yet. And the second one is that you hope someone like that is out there. So with this one the first has a better attitude, because he or she is thinking positively.


But with this one I am confused:

Me gustaría encontrar a una persona con la que lo pudiera compartir todo.
Me gustaría encontrar a una persona con la que lo pueda compartir todo.

How does the meaning change with using a present subjunctive vs a imperfect subjunctive? (and also why is the lo needed?)