Then the real question is: what is your main goal for making this game? If it's to finish a good game, use the generator and commission the changes. If it's to have fun making something with your friends, don't pay for anything. Learn how minor adjustments of eye placement, face, ear, and nose length and such make a big difference in how old someone looks and have someone within your group make the adjustments. Or not at all and learn to work around it. If it's to become a new game company and produce commercial games then commission someone to make all the faces from scratch, be prepared to spend lots of money on this game that you may not recoup, and try to find a permanent artist. Whatever you decide make sure that the goal is the same for the entire group or it will fall apart.
From they way your talking it sounds like you and your friends are doing this for fun but you're putting enough effort into it that you're thinking "Hey, why don't we try to make a little money off this thing too by going commercial?" Don't do that. It may seem like two goals that are similar enough to do at the same time, but they aren't at all. For one thing, a business relationship is a completely different thing, one which sometimes requires you to treat the other party in a harsh, cold, or demanding way. Most friendships can't survive that. For another, a game made for fun is an entirely different product from a game made for money. For fun is all about what you want, for money is all about what will sell best. It's like the difference between fine art and commercial art. Lastly, everything changes when money is involved, you have to worry more about if everyone really is pulling their weight, how to divide the money, how to sell the finished result, how to deal with taxes, ect. It's a lot of work and not something you should do on a whim.