This isn't scientific fluff I was answering your questions directly.
You asked, "Do we know exactly what human DNA was like 10,000 years ago or is this guess work? Is there evidence that suggests that mutations can increase new information as opposed to just modifying pre-existing information?"
I told you.
As I said, you can educate yourself. Cambrian is an interesting event but it neither proves or disproves that mutation is happening around us. Once you accept the premise that DNA is changing andf that humans are different now than they were 200 years ago, or 400 or 10,00 you will only be able to conclude that evolution does happen.
I am not an expert on Cambrian events, how can I answer that when I am merely providing evidence to you from other sources. How about you read what the experts say, and not what I say, as I don't claim to know the entire detail.