I was wondering the same thing.
Is it possible to add bonus feats to a list for a particular archetype? For example for the Scaled Fist there are additional feats which can be selected as a bonus feat for 1st level (Dragon Style, Intimidating Prowess) 6th level (Dazzling Display, Dragon Ferocity) and 10th level (Disheartening Display, Dragon Roar, Shatter Defenses).
Custom Archetype
Or the ability to change the stat from which all AC bonuses and spell progression...etc are calculated from. Then you could truly create nearly any archtype manually if you could change that.
I was hoping you could expand on the Unchained options to include the Scaled Fist version which is based on CHA. This version would make the multiclassing with Sorcerer nearly automatic for me but I can't change the main stat to CHA instead of WIS on the Custom Character build sheet. I guess if there were a field to change the main ability score calculations for AC etc on the Custom Character Build that would actually be ideal.