Too Few Guests!?

HELP! My hubby and really want to plan a vow renewal since our wedding didn't go as traditionally as we would have preferred (minor understatement!) the first time round. My dilemma is that we dont know very many people. How many guests is too few? Right now our list is only upto about 15 that we would want to invite.

The ceremony would take place in a beautiful outside location, of which there are plenty of options where we live so this is not a concern. The reception is where I'm struggling. I dont want our guests to be bored. Our idea for the "reception" is just an elegant dinner in a fine dining restaurant with live jazz. Do you think this would work? What elements do you think we should add (if any) to pad out the event?

Our main motivation for wanting to do this renewal is that we had only known each other for a very brief time when we tied the knot. Now, 5 years on, we feel we are at the stage now where we would naturally be talking about getting married, had our beginning been a bit more conventional. We never had proper photography (I have 1 or 2 candid smart phone photos that were taken by guests of that day that I actually like) which really saddens us. Our vows will be so much more meaningful now, since back then we were more or less taking a chance of one another. Now we have built a foundation and want to honor it with a more formal event. I value tradition, despite my crazy getting married on a whim! And I just want to solidify our union and make it "proper". I would like for hubs to wear a tux and for me to be in a floor length art deco/gala style bridal dress. Not the traditional white poofy gig with tons of tulle, since I recognize this is not a wedding. But just to give you an idea of what o have in mind visually...

I am English and my hubby is American. We live in Charleston SC.

Any thoughts/ideas appreciated!

Thanks! Xo