My question is: ...One of these are going to be my survival gun. Which one should it be and why?
That depends on a few things.
First, Mini-14's out-of-the-box vary in accuracy. How accurate is yours? SKS's also vary in quality of manufacture and accuracy, so the same question holds there. And within this question, how about at 50 yards vs 100 yards -- depending on which distances you feel are most relevant.
Another question for you is, what does "survival gun" mean to you?
If it is HD, do you live in a rural or urban environment? If "survival" in your definition includes hunting, what would you imagine you'd be hunting, and what would be the range of the shots you'd be taking?
When preparing to 'survive', we are only limited by our imaginations. You can go to the fringe and think "invading armies" or the old generic favorite, "zombies". Or take a more historically relevant approach, thinking "natural disaster" (for instance) and that you'd be sitting tight at home for a few days, waiting for normalcy to return, and hoping that no one tried to loot your house and force you to defend it.
Personally, the closest comparison I have to your question would be my accurized Mini-14, and my Arsenal, Inc. AK-47. If I were woken up in the middle of the night by a hoard of approaching zombies, I would grab the AK. If a nuclear bomb went off upwind of me, the roads were clogged with thousands of people trying to escape nearby cities and I had to leave on foot in a hurry, I would grab the Mini-14. You see, it's all about what you are willing to imagine and what you think you are going to be prepared for.