Lights shouldn't be a problem unless your handlebars are especially narrow.

Both my winter and "rest of the year" bikes have drop bars. Some people like sitting more upright than they can on a typical drop bar bike but for me it's a non-issue. When on either the drops or the tops, I'm sitting up high enough to get a good view of traffic.

I like using a road bike for my commute but the roads are generally in good shape. If it was nothing but pot holes for 12 miles it would take all the fun out of using the road bike and I'd want something with wider tires. As far as flats go, I had one flat all year last year and that was on a tire nearing the end of its life. I've had other years with more frequent flats when using tires with less flat protection.

I didn't check what tires came with the bike, but often the stock tires aren't very flat resistant. You may have to include new tires in your budget.