Sorry, was busy being high on caffeine and manga, so let me properly address this here. The *Dual Ability* and Skill Path combinations are similar, but has two distinct outlines. Dual Ability Vessel bios retains their Adv. Ninjutsu and or Mode slot; as like how it is with normal rules. The skills you pick within that line up; are swappable with one canon ability, so I'll use my Iyanna biography as the example.
She currently carries the KG + KG combination, but still retains her mode/AN slot, so I may still have that, but if I decided I wanted Obito's Mangekyou Sharingan; I would have to replace a KG slot on my combination with it, now counting as my canon ability but retaining my other KG and Mode/AN slot. What was confusing is that it was originally intended on only being an Adv. Ninjutsu slot, but we decided afterwards that modes will remain in play for the sake of making sure no one's builds are directly affected by Vessel System rulings.
Kooljay was informed of the lack of a mode slot prior to us shifting the rules around, and not realizing I didn't get back to him to inform of this change. So in his instance, he now would want Saskue's EMS (Canon/KG) + Mysterious Peacock Method (HA) + Sage Mode, this is valid.
However what he originally got approved was the Skill Path variant, which allows a custom Vessel bio to instead carry two Canon Abilities, i.e Sasuke's EMS + Raikage Armor + AN slot. This variant of choice does not allow for the Modes, aka the one's mentioned in the threads (Atavistic Flames, Curse Mark etc) to be chosen, but a Canon specific mode like Wood Sage Mode which is unique to Hashirama to be selected.
I hope this clears up any miscommunication on this moving forward, I will adjust the thread to mention Dual Ability bios still retain the slots to avoid any further confusion.