It is a nice enough name, but depends on surname. You wouldn't have an Aidan Caydan would you? Also be careful what the initals spell out. You wouldn't have Aidan Simon Smith - ASS.
It also depends on the rhythm of the name and how many syllables is the surname. That gives the clue for the middle name.
If you have a one syllable surname - you have a one syllable middle name i.e., Aidan Charles Jones or a three syllable middle name i.e, Aidan Harrison Smith. You wouldn't have two syllable middle name. i.e., Aidan, Jamie Thorn.
If you have a two syllable surname - you go for a one or three syllable middle name. i.e., Aidan James Potter. Two or three sound odd. i.e., Aidan Frederick
If you have a three or more syllable surname you go for a two syllable middlename - i.e., Aidan Lawrence Fredericks