If they were gonna be some kind of trixter dragon thingy than i think Charisma is important.
Okay, so how about we take the Pseudodragon and give it -2 Con (so it has Con 11 like the
Dragon article Fox) as well as +2 Cha?
The Fox also has a much higher Dex than a Pseudo (19 vs 15), so we could give it Dex 17 and a lower natural armour than the Pseudo's +4. Maybe +2 NA like a Dire Fox or +1 NA like a Dog?
Hmm, if we give it +1 NA that'll give it AC 16, same as a Dire Fox, but if we want AC 18 like a Pseudodragon it'll need a +3 NA with those ability scores.
I don't mind giving it a lower AC than a Pseudo, since it's got fur instead of scales, so I'll vote for +2 NA for the moment.
Foxdragon: Tiny Dragon, Str 6, Dex 17, Con 11, Int 10, Wis 12, Cha 12, +2 natural, AC 17 (+2 size, +3 Dex, +2 armor); touch 15, flat-footed 14