Mayo would be fine. The flavor will be a bit different with the missing seasonings, but I'm sure it will still be delicious.
Oh, by the way. I just reread the ingredients and see it uses salad dressing (miracle whip I presume) instead of mayo. I never buy miracle whip. Would mayo be OK to substitute? If not I'll get a small jar.
Thank you for the quick reply. I'm absolutely going to have to try this. It's intriguing. I'll let you know how it turns out. Maybe over the weekend.