[blimp]

I can only answer the very last question.

It shouldn't get below 5C, especially around that period. There are however a couple of buts, and they are important to keep in mind.

1. it could very well be below 5C
2. it could rain. even if you wear rain gear, you will get wet meaning that the chill factor will increase
3. it might be windy meaning increased chill factor.

Still it might be between 10-15C on the top. It is difficult to say and that is the beauty of a mountain, it has its own weather.

I've climbed it once much later than you will, and while it most likely wasn't below 5C even on the top it rained throughout the whole climb and it was very, very cold.