I have just come back last weekend and krakow was overall very quiet. I would suspect you won’t need to book. We got in no problem.

Hej. I do not think so. All in Polish.

Today as we are leaving everything is closed. Auschwitz is closed for 2 weeks.

To be honest it's difficult to be certain that the tower will be open. The day that we went it was closed, even though all the information said it was open! I suggest you e-mail the official Krakow Tourist Information Office (Magiczny Krakow) However, as the previous answer noted, Poland has now reported a confirmed case of COVID-19 and legislation is underway to give the prime minister additional powers to combat the virus, so measures may be put in place to restrict access to some places - who knows? But there are presently no travel restrictions in place, so I hope all goes smoothly with your trip.

Would be best to buy the ticket soon as the bell tower opens for business that morning. Tickets are very limited so you should try and capture at the soonest opportunity, as there is a certain allocation for the whole day.

It was warm when we visited and I had a short sleeved t-shirt on and so did most people. There seemed to be many people in shorts too especially men. I hope this helps a little.

Органные концерты обычно проходят в костеле Петра и Павла, это в 5 минутах пешком от Главного Рынка (площади)

I believe it is cash only. Local currency. It is kind of a pain to get the tickets. But all worth it once you step inside and see the altar opening. I took pics, video etc. Which was nice as it is not allowed at Wavel Castle. No flash is allowed - I believe.

je ne sais pas , les heures de fermetures sont tôt

we were there in august, we heard nothing about it closing in september