You should try to.

1. Which is better, or is either good?
a) Although it is not easy to overcome your own feelings, you should try.
b) Although it is not easy to overcome your own feelings, you should try to.

2. Which is better, or are all three correct grammatically?
a) Whoever comes by today, I'll tell them that I will not go out.
b) Whoever comes by today, I'll tell him that I will not go out.
c) Whoever comes by today, Ill tell the person that I will not go out.

Thanks in advance.
Kamo