Can you benefit from the Defense fighting style while not using armor AC calculation?

Question

Let's assume a Lizardfolk fighter, with the Defense fighting style, wearing leather armor. Lizardfolk, per Volo's p. 113, get Natural Armor:

You have tough, scaly skin. When you aren't wearing armor, your AC is 13 + your Dexterity modifier. You can use your natural armor to determine your AC if the armor you wear would leave you with a lower AC. A shield's benefits apply as normal while you use your natural armor.

Emphasis mine. Leather armor gives a DC of 11+Dex but, according to the above rule, I am allowed to use my superior Natural Armor DC of 13+Dex (this is different from mage armor and Draconic Resilience and which I almost asked about, but they specifically disallow wearing armor).

Now, at the same time, I'm wearing armor, which should qualify me for my chosen Fighting Style, Defense (PHB p. 72):

Defense: While you are wearing armor, you gain a +1 bonus to AC.

Emphasis, again, mine - it doesn't say anything about actually using the armor's AC.

Could I combine the two to claim an AC of 14+Dex?

Answer 1

Yes you could

The defense fighting style, as you mentioned, states

While you are wearing armor, you gain a +1 bonus to AC

The condition of wearing armor is satisfied, as you are indeed wearing leather armor. Additionally, Defense states exactly "+1 Bonus to AC" no ambiguity there.

Your character, although having a thick hide, can benefit from it's fighting style and use his armor better than most, therefore granting him the bonus. It is not a magical effect from the armor, it's a fighting style your character has.

Your character is the one gaining AC from Defense, not your armor!

Answer 2

Unclear

A strict RAW (rules-as-written) reading of the requirements for the Defense fighting style would definitely suggest you can gain the +1 to your AC while wearing leather armor. The question is whether this bonus will also apply to your "natural armor" AC calculation.

There's nothing in the core rules to suggest otherwise. But there is a ruling on a similar issue that muddies the waters. The following exchange occurred on twitter:

Dave Williams: Lizardfolk natural AC implies you can use it while wearing armor. The +1AC bonus from magic armor says it applies to you while wearing the armor. So Lizardfolk with 13+Dex+1 AC if they are wearing +1 Leather?

Jeremy Crawford: The AC bonus that magic armor confers to you while you wear it is a property of the armor. That bonus doesn't apply to other AC calculations you might have.

This may be significant, because the wording for the AC bonus of +1, +2, or +3 magic armor is remarkably similar to that of the Defense fighting style.

You have a bonus to AC while wearing this armor. (DMG, p. 152)

This might suggest that your +1 to AC only applies when you are calculating your AC via your leather armor, not to the calculations you make when using your natural armor.

However, it's worth noting that a twitter exchange in response to the tweets above suggested that we shouldn't be too quick to extrapolate to other cases from that answer.

Dave Williams: Regarding the intent for Lizardfolk using natural armor while wearing magic armor does that same intent apply to magical armor properties other than the AC bonus?

Jeremy Crawford: My answer was only about +X armor.

Ultimately, your DM may need to apply their own judgment here. Jeremy Crawford even suggests this in response to the magic armor question.

Jeremy Crawford: If a DM wants the AC bonus conferred by magic armor to apply to the natural armor of lizardfolk, nothing in the game will break. And that DM is making a reasonable call based on the wording of the armor's description. I shared our intent, but the DM decides.

Answer 3

RAW is unclear

No you couldn't

Natural Armor (VGtM p. 113)

You have tough, scaly skin. When you aren't wearing armor, your AC is 13 + your Dexterity modifier. You can use your natural armor to determine your AC if the armor you wear would leave you with a lower AC. A shield's benefits apply as normal while you use your natural armor.

Defense (PHB p. 72)

While you are wearing armor, you gain a +1 bonus to AC

The natural armor calculation only applies when you are not wearing armor. Note that the bolded text is after a period but before a comma. The bolded text is in the same sentence as the AC calculation. It appears that RAI would mean "if the armor you wear" would be instead "if you wear Leather armor (11+DEX) you can take it off and use your Natural Armor (13+DEX) instead". This may be a case of trying to condense the wording to save space which is poorly done. The offending sentence could instead read "You can use your natural armor to determine your AC if the armor you would wear would leave you with a lower AC." The description of the Defense Fighting Style requires worn armor.

Yes, you could

Natural Armor (VGtM p. 113)

You have tough, scaly skin. When you aren't wearing armor, your AC is 13 + your Dexterity modifier. You can use your natural armor to determine your AC if the armor you wear would leave you with a lower AC. A shield's benefits apply as normal while you use your natural armor.

This interpretation says when you are wearing armor you can choose which AC calculation to use.

Conclusion

The wording is bad on this ability and can be interpreted different ways. Overall, it would be up to the DM which interpretation to use. The majority of the answers and designers etc. would agree with the latter.