“you must have a pair copy the exact same sexually-related mutations and find each other in order to re-produce this ‘new’ species”
A highly significant argument. If a refutation can be found by the opposition, I’d like to see it.
Say you are the first human in malaria country to derive the sickle cell anemia gene in one copy in your genome. You pass it on to half of your offspring. Those who have one copy of the mutation survive malaria better than those without it. As such natural selection favors your offspring in malaria country, and all your children with the gene go on to have many children and grandchildren.
Eventually those grandchildren intermarry - and suddenly an individual can get the sickle cell anemia gene from BOTH parents, and develop sickle cell anemia (and most likely die), have only one copy and survive malaria, or have no copy and probably die of malaria.
So you should be able to see by this example that there is absolutely NO REQURIEMENT AT ALL that the same mutation happen twice independently before it can be passed on (and proliferated) through a population.
Creationists. They don't know much, and what they think they know just isn't so!