The reason Alan had wanted Edward to stay back was simple. He wanted to try out the various methods listed in the manuals that had been given to him. He had studied these damn manuals for two weeks.
And although he was still a bit confused at some parts, he understood the majority of them.
The avian tribes, those that descended from the mighty Phoenix, didn't necessarily all use fire. That was the first surprise to Alan. He expected every one of them to use fire. This was helpful in some regards.
Alan was, before everything else, a frost dragon. One that did not go well with fire at all. Even with the increase in affinities, he had experienced due to absorbing the drop of ichor of Ariel.
He didn't have a single one that was similar to, or even had some compatibility with, fire. Hell, one could even say that with all these attributes he had, his major weakness was fire.