Hi Audge,
Apart from the physical challenge from starting in Pamplona (due to the bad condition of your ankle), you might also want to consider a place somewhere closer to Santiago to avoid walking "against the clock". I believe you'll much more enjoy your camino if you forget time and can do whatever you want to do. If you like a place, you stay, for example, even if you've only walked a few miles. If you do not care about taking a bus; you can forget this argument.
Now your questions:
From/to most small towns there are busses to and from the big cities, but they travel only a few times or even once a day. You'll have to ask the locals how late and where the bus will arrive. Bus-stops in Spain aren't always recognizable.
It's never to late to make camino buddies; most of the friends I made on the camino, I didn't meet in SJPP. So I wouldn't worry too much about that. As long as you are open to other people, you'll sure make friends.
Don't worry, as long as you listen to your body, you'll be allright. Buen camino!