Celestial Patron Two Weapon Fighting?

I was trying to utilize the new Infernal Bulwark feat on my primarily Celestial Patron Warlock class, but couldn’t decide what to do with having no shield and needing too high of a dexterity build to make a high enough strength for two-handed weapons. Then it just hit me. Twice! Ow!

Unfortunately I’m a little rusty when it comes to dual wielder and the defensive duelist feats. As a Celestial Patron Warlock with the Boon of Recovery and Searing Vengeance, I’m trying to have as high of a constitution as possible so i get more back when I “rise again.” That’s one fewt as an epic boon.

Of course, dual wielder and defensive dualist both add dexterity instead of constitution. That makes three total.

Finally, I mentioned infernal Bulkwork which can boost my charisma. Combined with a +2 in charisma to take me up to a 20 makes all 5 feat/asi slots. That leaves me with an odd number in Constitution.

My current fighter 1/ Warlock 19 build has an even 20 in Charisma and Constitution but does not feature the two two weapon fighting feats. 

I’m sure similar questions have been asked before, and I’ve tried looking up what I can again with limited success on how it applies to this build. So, could someone help me out here?

www.dndbeyond.com/sheet-pdfs/Actionsparda_165040730.pdf

Update: I think I found a ln asi/feat pattern that works and gives me even numbers. I’m just not sure if I’m taking them in the correct order. Tell me what you think:

4: Warcaster (Charisma) - Charisma from 17 to 18

8: Dual Wield (Dexterity) - Dexterity 14 to 15

12: Defensive Duelist (Dexterity) - Dexterity 15 yo 16

16: Infernal Bulwark (Charisma) - Charisma 18 to 19

19: Boon of Recovery (Charisma) - Charisma 19 to 20