Coin locker

Hi.
I'll travel to Japan next November but I have some questions about my luggage.
I need to know if there are coin lockers for hand luggage at Okayama and Hiroshima JR stations.

Also, I go to Himeji but I go from my ryokan, outside Himeji and, when I finish my visit to the castle, I go to the JR station. So, do you have if is there any coin lockers (or any place to leave our hand lugagge) at Himeji Castle?

We'll travel, also, Tokyo-Kanazawa with JR with all the luggage (2 big cases and to 2 hand cases) but we'll travel Kanazawa-Ogimachi village and Ogimachi Village-Takayama by bus. Do you know if we can carry that big luggage inside the buses? And, a very important question ... is there any place at Ogimachi bus station (November, 22th, I've read it has a different stop?¿?) to leave all the luggage? We don't sleep at Ogimachi.

If you don't know the responses, may you say me where can I ask for them? english ...

Is it mandatory to reserve my trains when I travel in local/ express/limited express/shinkasen?

Thank you very much!!!