Off white shoes with pure white dress?

I think either pair would look great with your dress, so I'd pick the pair that is more comfortable.

Agreed with Barbara

Ivory ("off white") photographs a shade lighter no one would notice such a minor difference in shade! I'd go with whichever you like more

Honestly, the white ones look TOO white, to the point that the fabric looks cheap. Your dress is long (so pretty!) and no one is really going to get a great look at your shoes. It's your day, wear the shoes that will let you dance the night away!

Your dress is gorgeous. Nobody will see the shoes and even if they do (as in, you lift your dress to show them!), they will not notice the color difference. Wear the pair that is more comfortable. Seriously.

Typically, it works to have the shoes slightly darker than the dress, but not lighter. Given that the shoes will be in the shadow of the dress, no one is likely to notice if they are slightly darker, anyway--they'll just assume it's the shadow.

I vote for the more comfy pair

No one will see your shoes. They will be to busy staring at that beautiful dress!