Item Number One
Ok, let's say that since God created all things with an appearance of "maturity": the earth, universe, plants, animals, and people were mature.
Does this imply that light was also mature? And what does that mean anyway? Light being mature? Mature light, a Creationist would say, is light that has been created everywhere at once.
Lets say that star A has been created. It's light is immediately being emitted, but God made light all over the universe in all places to appear as though it was coming from this star. So, on Earth, God created some rays of light that appeared to be coming in the direction of that star--a star that is millions of light years away. This gets somewhat complex!
Assuming that God made light rays all the way from the distant star to the earth, then what does that light show us? When the light reaches earth, do we see how it looked on Day 1 of creation until the light emitted from the star reaches us a million years later?
And what if a supernova occurs? Guess we'll have to wait until the created light all reaches us, and the regular light is emmitted, to see the supernova.
Wait, but we have already seen supernovas. How can this be?
This type of an explanation does not satisfy me. God never said He did anything like this.
Even the sites in the OP admit that item no. one is out of the picture:
"This would mean that for a 10,000-year-old universe, that anything we see happening beyond about 10,000 light-years away is actually part of a gigantic picture show of things that have not actually happened, showing us objects which may not even exist."
Item number one has been refuted.