Wedding Ceremony/dinner at small restaurant

I think that the kids will be fine, assuming this isn't going to be a significant multi-hour affair. The ceremony shouldn't take longer than a half-an-hour. I imagine most photographs will be taken during the ceremony and family candids at dinner. That leaves around a .5-1.0 hours or so for the photographer to take pictures of just you and your spouse, during which I imagine your family will mingle and begin finding their seats. After which, dinner will last around 1-2 hours, max 3. And at that point, I'm sure it would be okay if a parent has to excuse themselves early because their toddler is having a fit LOL.

If you're super worried, and you have the restaurant booked for just your party, you could see if they could put out activities for the children on the table such as coloring books and crayons. That would be a quiet activity that'd be easy enough to hide away when it comes to dinner so that your photographs still look nice.