You miss the point. First of all, evolution tells us that organisms DO reproduce after their kind. The theory would be falsified if we ever saw a cow giving birth to anything but a cow, for example. So as far as what a human could observe in his or her lifetime, the Biblical verse that says that animals reproduce after their kind is certainly not in error. We will indeed never observe organisms not reproducing after their kind, but evolution is perfectly consistent with this.
As far as creating the structure of the week for us, it was unnecessary to use a six day creation to do so. Why not just say that a week will be seven days, and that we should use one as a day of rest and worship? Why use a creation PROCESS to do this. I think that's totally backwards. The creation didn't last six days so that we'd have a sabbath; we have a sabbath because the creation lasted six days, and God rested on the seventh. Why should a week be seven days anyway? God gave us natural phenomena we could use to measure other time periods, such as the rotation of the earth to measure days, the orbit of the moon to measure months and the orbit of the earth to measure years. Where is the natural pheonmenon that corresponds to a week?
As far as death and mutation goes, why wouldn't God say that a system involving change is good? Why must something be eternally unchanging to be good? Why can't death also be good? For example, if there were no death, as the Bible claims was God's intention before the fall, then assuming a relatively low birthrate of just over 2% and, of course a 0% death rate, then given 10000 years or so since creation, there would be a human population of ~1 x 10^100 people on earth! Assuming an average weight of a human being to be 50 kg, this would yield a weight of 5 x 10^99 kg. This weight is much greater than the weight of the earth, by a factor of ~10^72! Even given an earth-like planet orbiting each star in the universe, we still would have a population of ~10^42 people on each planet. Clearly death is a good thing. Note that even if you assume a lower birth rate, you don't solve the problem, you merely postpone it. Eventually, without death, the population will become too great for the universe to support. When the Bible says that death began with the fall, I believe it meant that the spiritual death of hell began then, so I still believe that the Bible is inerrant.
As far as six literal days goes, you again miss the point. It very well could have been six days from God's reference frame encompassing the entire early universe and still be billions of years from our reference frame. Your statement that it really was six literal days simply doesn't make sense physically. The whole point is that six literal days is correct, but so is 15 billion years. If that doesn't make sense, then you are still stuck thinking of time as an absolute quantity. Time is subjective, so when we say creation took 15 billion years, we say so from our refernence frame, and we are correct in saying this. When the Bible says it was six days, this is the case from God's reference frame, and it also is correct to say this.
So if it wasn't a special creation, where did all the species that we have on earth come from if 'we will indeed never observe organisms not reproducing after their kind'? Are you saying that you don't believe that speciation occurs? You know, every once in awhile, we have to step back and make sure we are on the same page with the same language. From an essay by Laurence Moran entitled 'What is Evolution?'on the Talk Origins website, I've copied the following definition:
"In the broadest sense, evolution is merely change, and so is all-pervasive; galaxies, languages, and political systems all evolve. Biological evolution ... is change in the properties of populations of organisms that transcend the lifetime of a single individual. The ontogeny of an individual is not considered evolution; individual organisms do not evolve. The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next. Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportion of different alleles within a population (such as those determining blood types) to the successive alterations that led from the earliest protoorganism to snails, bees, giraffes, and dandelions." - Douglas J. Futuyma in Evolutionary Biology, Sinauer Associates 1986
Do you agree with this definition? I don't think many who believe in a special creation would disagree with it either.... until we get down to that last little bit where gears are shifted from talking about general changes and changes that are 'inheritable via the genetic material from one generation to the next' to where he is talking about 'the successive alterations that led from the earliest protoorganism to snails, bees, giraffes, and dandelions.' Are you going to tell me that this last part of Futuyma's definition is fully in line with your statement that 'We will indeed never observe organisms not reproducing after their kind, but evolution is perfectly consistent with this?' Clearly there's a disconnect here. If your statement is true, explain to me the origin of all the species we have today. Are you saying that you believe that all the species we see today did not descend from a common ancestor? As time progressed, different lineages of organisms were modified with descent to adapt to their environments as well under other influences but only within their own species? Thus for you, evolution is not a branching tree or bush, with the tips of each branch representing currently living species? What then? Is your theory that each species had an original set of parents that appeared in the ocean soup and there was no common ancestor for all the various species?
As far as creating the structure of the week for us, it was unnecessary to use a six day creation to do so. Why not just say that a week will be seven days, and that we should use one as a day of rest and worship?
Here's a thought for you. God was so adamant about observing a day of rest once a week for worship that He modeled it for mankind. He worked for six days and then he rested. Read the commandment that refers to this. Exodus 20: 9 Six days shalt thou labour, and do all thy work: 10 But the seventh day is the sabbath of the LORD thy God: in it thou shalt not do any work, thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor thy stranger that is within thy gates: 11 For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it.' You have produced some good reasoning as to why the 'days' could be much much longer than that but when you read the above in conjunction with the original Hebrew that refers to the days of creation as 24 hour periods, it gets tougher and tougher for me to swallow anything longer than a 24 hour day as a possibility. So I suppose an answer to your question as to 'why 6 24 hour days is simply that God treats the Sabbath so seriously that He Himself modeled directly how we are to live our lives. I'm in part speculating but I don't have a better answer than that.
It's a good one to muse about but there really is no answer for it because it's all purely hypothetical. At the time the earth was created, it was before the fall of man so the creation was perfect. It was a different world and it operated under a different set of rules. Beyond that, the Bible doesn't give many clues about how the population scenario would have been handled.