Science is flying blind. They have no idea how DNA originally was or nature was, so all they can do is stab in the dark, looking for present state explanations. No wonder they have no clue at all what 91 percent of the dna even does!
We have an awful lot of information about what DNA does and how it changes over time. 'Stabbing in the dark' is hyperbole, and a complete mischaracterisation of the situation, as I will explain.
No. The unknown part implies nothing at all but you not knowing. The bible implies that God created, so all the dna has to either have uses we don't know about, or once did in the former state...or both! It implies that man is not related to chimps.
Since we are discussing evolution versus creation, what the Bible says only characterises the creationist view. It doesn't in any way limit the evolutionist view. 'It implies that man is not releated to chimps' is a non-sequitur, I cannot see any link to the previous statements.
The considerable similarity of human and chimp DNA is very strong objective evidence that we are related. Note that this is backed up by mitochondrial DNA, etc.
No. There is absolutely no evidence for that. The idea that heredity has to be the way DNA used to be passed down in the former nature is impossible to prove. That is just a belief based on how it now works.
We have a lot of evidence that DNA is the main part of heredity for pretty much all living and near to living thigns. (RNA viruses are an exception). This is true for the most advanced organisms (higher plants and animals) to the most primitive (archaea, prokaryotes). It is a reasonable belief, backed by that evidence, that DNA has been the main part of heredity since at least these organisms evolved.
Since these organisms evolved well before chimps and humans diverged, that is good evidence that the common ancestor of chimps and humans also had DNA which was the main part of heredity, and that what makes chimps and humans different is mainly down to the changes that have occurred in DNA.
I believe that you are doing what creationists often do. Which is to leap on any form of uncertainty anywhere, and try to amplify the consequences of the uncertainty to repudiate much more than is logically reasonable. Your argument looks to me to be 'We don't know everything about DNA, therefore we know nothing and can make no conclusions.' It doesn't, we are unsure about some things but much more sure about other things. It's the other things that we are very sure about that allows us to use DNA to measure relatedness.
We don't know the function of all DNA. However, we do know that DNA is involved in heredity, codes for proteins, transposons, messenger and other RNA etc. We also know how it mutates over time, is conserved or not by selection. Hence, looking at the raw DNA base sequences allows us to measure relatedness between species, and estimate the time of the last common ancestor.
I'll give you an analogy. In the old days before printing, books were copied by hand. Occasionally mistakes or other changes would be made during copying, and copies of the copies would likely repeat the same changes, as well as add other ones. From this, it is possible to put books into a 'family tree' based on how they were copied.
Now, imaging that the book is in Arabic or some other language that you don't understand. (If you understand Arabic, please substitute another language). Even though you would have no idea what the words of the book mean, you would still be able to find changes and form copies of the book into a family tree. The same applies to DNA of humans, chimps, and other things. What the function of all the DNA is, is not all known. However, we can read the code (see previous links for genetic code for organisms), and this is sufficient to put organisms into a family tree.
If you think it isn't sufficient, then could you please explain why. Just using hyperbole such as claiming that science is stabbing in the dark is not sufficient. We know a lot, not everything, about DNA, it's role in life, and how it is affected during evolution. The family trees and measures of relationship are based upon very good information, and labelling it 'stabbing in the dark' does not work unless you can come up with a strong argument as to why it should be seen as so.