How consistant do I need to be? By that I mean, I may be able to take Taz out once a day by himself so that we can work on these things individually. But our other walks will be with Ginger. Would the fact that I am paying closer attention at some times and not others confuse him?
Not at all. When I mean pay closer attention, I really mean for you to change the way you look at your dogs. You know how some people say losing weight isn't just a diet; it's a lifestyle change? Fixing Taz's behavior isn't just a quick training session; it's a mentality change. Rather than "Oh no! He lunged. What do I do now?", you will instead think "Hmm...his eyes are getting hard, his muscles are getting tense, and his tail is wagging stiffly. What can I do to reframe or diffuse this situation?"

In both instances I feel I am acting normal not really thinking about what we are doing and find myself reacting to their unexpected behaviors.
From this point on, you are not the reaction. I remember that phrase from Les Choristes, "action-reaction". This is NOT the route you want to take. Rather than waiting for Taz to lunge, you will assess him as soon as you see his triggers (which sounds like young children and strange dogs staring at him). As soon as you see these triggers, you will notice Taz beginning to feel uncomfortable or tense, and you end it there. You can end it by click/treating him and playing the meeting game. You can end it by removing him entirely from the situation. You can tell the kids or dogs to back up. You can recall him to you and leave, etc.

So, yes, initially, you will need one-on-one training sessions with Taz so that you can get a feel for what sets him off, at what point do things set him off, and how you can reframe the situation. When you're walking both dogs, you need not pay so close attention to his every move, but you *do* need to quickly and thoroughly assess him as soon as you see a small child or strange dog approach you.

If you need more ideas of coping skills, just let me know! I love this topic with a passion, and have many tricks up my sleeve