McDonald has always denied asking the victim if Evans could have sex with her, as Evans claims
It is true that McDonald said that Evans asked the victim if he could have sex with her whereas Evans says that McDonald asked. Both agree that she was asked and said yes. It may be that the original jury took this disagreement as evidence that neither of them actually asked the girl and she did not consent. If the prosecution had gone with that line they may have got a different result, although I'm not convinced they would. It is not uncommon for people to attribute something they said to someone else when recounting an incident. However, the prosecution went with the line that the victim was too drunk to consent which, in their eyes, would make this disagreement irrelevant.
Witness offers no information as he isn't asked because the reward hasn't gone up yet
The witnesses (there were two, not one) gave information but were not asked about details of their encounter with the victim - positions used, words said, etc. That has nothing to do with the reward not being available. It was simply that the lawyers defending Evans did not realise the answers could be relevant and so failed to ask the questions. In one case their main interest in the witness (who came forward before the initial trial) was to counter any suggestion by the prosecution that the victim would not have sex with a stranger she had just met - an argument the prosecution did not, in fact, make. The other witness came forward to the police on the day of the original verdict, apparently because he could not understand why the victim slept with him 2 weeks after the rape. In his first statement he described the victim's loss of memory every time she spent the night with him but the defence did not pursue this when they first attempted to appeal.
it's only his word
It is the word of two men who do not know each other supported to some extent by text messages and evidence from the mother of one of the men (this particular witness was living with his mother at the time of his encounters with the victim).
I believe he was friends with CE's sister and he was known to meet with CE's family on many occasions
As far as I can see this is not true. The prosecution would certainly have put it into evidence if it was.
Tristin Owens, the witness who contacted the police on the day of the verdict in the initial trial, does not appear to know the family directly but one of his friends is also a friend of Evans. His mother, who was able to partly confirm his evidence, is a close friend of the victim's mother. Steven Hughes, the witness who came forward before the original trial, also does not appear to know the family directly although he has a cousin who knows Evans.