Audio Quest Dragon on Neucleus speakers?..say it ain't so.
however, you need Neucleus matching speaker for center for sure, and preferable all around...otherwise it will sound poor for certain. You need a tonal match all across the front, at least, and preferably back as well. You will NEVER get a believable cohesive soundstage that dissapears and works together with mismatched speakers...waste of time really. You will otherwise always be aware of differences in sound, as it pans across the speakers.
Neucleus's are cheep, and there's no reason to not get matching units for it otherwise, if you plan on keeping Gallo's up front that is...Dragon????.....Hummmmm....