If I were going to use prong, and for that situation I find it can be counter productive unless you know exactly what you are doing and have great timing know exactly what strength correction the dog needs in and out of drive and have a good read on the dog in general, I would use a hard prong them out of drive correction but only if they had begun the lunging reactive behavior.
It stuns the behavior to a stop TEMPORARILY and then you can quickly follow up with the behavior you actually want out of them, but this only works if you did it exactly right and you pronged them out of drive but didn't prong them so hard they shut down on you.
My preferred method when they do the lunging thing is to pull straight up on the leash and leave em only touching the ground with their back feet. As soon as the dog sits or downs I let all the pressure off. Helps make lunging not fun and avoids building drive by accident by tugging directly against the dog in the opposite direction.
Before you got to the re-activity point I find it is best to ask for a behavior. Look, is usually the one I use. As soon as they look I reward with food or toy that has had its value built up in the eyes of the dog to the level it is essentially a tool. If I leave the house with the young dog I ALWAYS have one of the two ready. It becomes a habit for the dog eventually. It can even get to the point that when the dog is surprised by a trigger way in under the threshold they can be in the middle of the bark lunge behavior and when you ask for the behavior they look back at you and when you mark and throw that toy out they completely cease to give a crap that the trigger is even there.
Sri If you have a dog that is just frustrated it can't meet and on top of that was used to having that frustration built up from opposition reflex against a leash you might consider finding some dogs you know your dog won't fight and is fairly familiar with. You want them leashed and under control. When your pup does the bark lunge stuff you just hold him in place and keep holding him there until he calms down and either sits or goes into a down. Soon as that happens you mark it and reward the dog by allowing the meeting. If that happens enough times with enough different dogs you can put it in the dogs head you will only allow a meeting if he doesn't act like a complete idiot. Then you can go to a variable reward schedule for that and the dog starts to gamble, or the dog will just be more receptive to taking commands and following other methods.
The prong stuff for that kind of thing can work, but the problem I find with it is the dog can learn to associate the presence of strange people and dogs with physical corrections you can end up stacking stress onto the dog on top of whatever fear or frustration was already there.