If you want to have some options that don't require a lot of assembly, I would go with things like: breaded ravioli that you can skewer and coat partway in a nice sauce, any of the filled phyllo cups (usually come in a variety), spanakopita triangles (always a hit), or, believe it or not, pigs in a blanket with a nice stone-ground mustard dipping sauce. I spent a number of years doing banquet service at a 5-star inn that had a huge (still does) business in wedding and events. I always tell everyone that of all the high-class and labor-intensive apps that were served, the one that disappeared in a flash was the pigs in a blanket. I don't know if they bring back memories for people, but they get gobbled up. On the ravioli, the Rana brand is really good, for breaded and non-breaded. For the phyllo cups, if you got unfilled ones, you could probably find a premade sausage or mushroom filling at places like Whole Foods. Just pop in and good to go. Those go really well. Spanakopita triangles are always a hit and super easy.
I would stay away from wings if people are going to be eating them while standing during a cocktail hour. They are messy and there are bones left over so people are juggling a drink and a plate full of bones.
You may be doing something totally different and the above won't be of help, so FWIW.
Apparently, there is always wine. hhh