I think many people forget to teach a dog hand signals as well as verbal commands. There are times will come along where you will find this very valuable . For example, sometimes people are on the phone but the dog is getting into something they should not. Another is when you are having a conversation with another human face to face.
Hand signals can even save a dogs life.
So my suggestion until each dog learns its name is to use both their name, hand signals, and a treat to reward them when they comply.
I have two dogs I do train together. I have also trained each one in the basics individually.
There are many benefits of training two dogs together. If one learns faster than the other, then the slower learner can also learn by example from the other dog.
Treats are very important, but this can also get expensive. So for that purpose, I use plain Cherios and the dogs love them. You can even use the Generic ones you find in your local Grocery Store such as Aldi's. They are very cheap and you can put them in your pocket in a zip lock bag.
I would also suggest you invest in a very long lead and not a retractable one. This will allow you to give your dog some room so you can still maintain control while you teach them to stay. This is also a perfect lead to let them run around some in the park after you walk them on a normal lead. Our Basenji Roo loves this and knows exactly what is going to happen when we change his lead after a walk. So it is also an indication of play time for him.
I personally train my dogs for 15 mins or less each time I walk them or am running a training session in the house. You will find that if you use the Cherrios as a training tool, your dogs will really start to focus on you and be less distracted.
By the way I do not use a clicker because if you are around someone else that is also using one it can be confusing for your dog. Also if you are in a circumstance where you do not have your clicker or forgot it, then you still need to maintain control of your dog.
I hope this helps,