Hi Ella, you need half a day (4 hours at least ) I would say . We spent about 6 hours including the cable car ride was enough to see everything and grab some snacks.

Hong Kong is a huge city and it is unlikely that you will run into protesters especially if you visit during the week as most protests are on the weekends. If you are out on Lantau island where the cable car and airport is, then you have nothing to worry about.

We booked online but certainly can buy on site. Online saves you time in line

Yes there is a ticket office in the village and you can even buy your tickets there.

Noi ci siamo state ieri e la manutenzione era in corso. Dal 23 aprile a inizio maggio.... ci sono dei bus per salire

On rainy days can you see anything?

As in the previous answers....25 minutes is only 1 way. You'll need at least 2 hrs to 3 hrs to do this trip - to get in the queue to buy the tickets, get in the queue to get on the gondola, to walk thru the village, walk up the steps to see the big Budda (there's LOTS), to see the small village at the base then go back down. We did minimal touring through the village and it took us probably around 2 hrs total. BUT it's worth it!!

Yes it's closed until from 6-26 March 2019. "NGONG PING 360 CABLE CAR TEMPORARY CLOSURE 6th to 26th March 2019 - The Ngong Ping 360 cable car operating between Tung Chung and Ngong Ping is to close for scheduled maintenance from 6th to 26th March 2019 (21 days). Normal service will resume on 27th March. During the closure period Ngong Ping Village, the "Big Buddha", Po Lin Monastery, Wisdom Path and other attractions at Ngong Ping remain open as usual. Visitors can take alternative transport between Tung Chung and Ngong Ping, either New Lantao Bus Company service 23, which takes about 50 minutes and departs from Tung Chung Temporary Bus Terminus, adjacent to the cable car terminal on Tat Tung Road (additional services operate to meet demand) or, subject to availability, Lantau (blue) taxi, fare approx HK$180, journey time about 35 mins." Hope this helps.