i do shadow yoga and i def think it helps my running etc. it helps build core strength as well as all over strength. contrary to popular belief it is actually a very intensive work out. after some poses i am out of breath and my heart rate is high, and that is after being still, or slowly working through a pose.
to be truthful i'm not really sure about the training, maybe just work up to building up distance and use the 10km as one of the build up days, but once you have gotten as far as you have gone in training maybe from then do the run walk thing. or you could plan to run 1km then walk 500m (not sure how you would work that out). or you could plan to run/walk to a time plan maybe 15mins run 5 min walk. not really sure, how is your leg? did you manage to get the shoes.
If i know you pops you are going to want to run the whole way so maybe the using it as a training run and making it your next increase, increase your runs by 10% (or even a little more) each week and work out from that how much of the 10km you could run and make that your aim for the day running that distance and then walk/running the rest to finish the 10km. then you could continue on from there to increase your distances and if you can find a 10km run in a couple of months to do.