Before we start, let's make this clear: fate and destiny are pawns to God's will. On the issue of sovereignty, there is no question. Indeed, as we struggle to understand the nature of things, nebulous constructs like fate, destiny, purpose, super intention, and providence are useful.
Fate has a varied definition. Does it mean the consequence of our choices, like "sealing your fate" after untoward acts? Or does it mean an outside hand, like "fate dealt that hand" to explain why circumstances occur? Or does it mean the ultimate destination, from the shared root of destiny, like "you must accept your fate". Just saying "fate" doesn't really say anything at all.
Insofar as fate as a consequence, there is no issue. Consequences do follow decisions. In this context, none of the other terms really share this definition. I like to consider fate in this singular way.
Now, there's the concept of the outside hand. This is most like super intention or providence. Is it God, the devil, nature, or gremlins? Something somewhere is influencing things. I think providence is the best term here. It best sums the concept of an active observer, and squashes basic deistic premises God as an inactive observer. He's been clearly involved in the past and hasn't indicated he plans to step away.
Turning to fate as a destination, this is the ugliest use of the term. In no small part purpose and destiny are best transposed here. And of those two, destiny best indicates the destination. Knowing your destination does not preclude your destination, I might add. Those ascribing to predestination would not agree. However, the logic simply does not follow that destiny must be absolute.
There's this contrast with purpose. In no small part destiny seems to indicate the "where" or "what" of a journey's end. Your destiny is your destination. However, purpose seems to better reflect the "why" of such a journey. It addresses the reason and sometimes the intrinsic value of the journey.
Let's briefly dance with the mother of all terms, super intention. Super intention is the will of God, typically. It is what God wants or intends for our lives. The problem is not that God desires something. The question that has plagued man for centuries is if we are capable of accomplishing less, more, or just different than that intention. Is God's sovereignty compromised if God's intentions are not realized?
The issue falls back to free will. We know free will exists for God's pleasure to be volitionally loved. We know that free will is important so God's control over our actions does not result in God's preordainment of sinful acts. Free will seems important to make the world go 'round.
Many contrarians here would tell me that free will is illusive because it is a necessary idea for man in light of the ultimate consequences of God's ultimate sovereignty. That is, we don't really choose anything because God decided long ago.
I have an opinion on the issue of predestination. But to this particular discussion the only question required is, "Can God allow free will?" The answer to that tricky question opens windows of possibilities. And possibilities, the root of all evil, bring about a potential liberty in Christ.
And as we describe the complex tapestry of how God orchestrates all of nature, time, and the cosmos, it is terms like fate, destiny, super intention, purpose, and providence that we use like tools. We are attempting to say a number equivalent to infinity. Of course it comes up short. However, imperfect terms are at least terms. And with terms there is discussion. And with discussion, growth.