Subs for Mayo ??

  I'm hoping some of you seasoned chefs can help me.

I have a recipe that calls for both mayo and sour cream.  I'm ok with using FF sour cream, but is there anything I can sub in for the mayo?  What would you use?  I'm listing the recipe below with the link for the original post.  I read through the comments in the post, but I didn't see anyone subbing the mayo.

6 Boneless Skinless Chicken Thighs
16 oz can of artichokes (I'm subbing spinach)
1/2 c. mayo
1/2 c. sour cream
1 c. parmesan cheese (I'm subbing Mozzarella probably)
garlic - I'm adding
onion powder - I'm adding

Heat oven to 350
Place meat in greased casserol dish
Mix other ingredients and spread over chicken
Bake for 40 min

http://www.lowcarbfriends.com/bbs/lowcarb-recipe-help-sugges tions/566494-artichoke-chicken.html 

In some recipes, greek yogurt is a good substitute..I wouldn't spread it on a sandwich or anything as a sub but if there are other ingredients like the ones listed above it should be a great substitute!

 Love love laughing cow wedges and they come in different flavors!

I'd probably substitute light mayo but start with a 1/4 cup. Then I'd see if you have enough sauce to  work and then add yogurt and maybe a squeeze or two of lemon if you need more.

Egg?