Yes, nearly 90 % are largely populated by Buddhism followers with some minority of Tibetan Muslims, which you can notice in the cities of Lhasa and Shigatse.
Where in all hotels in Kathmandu and Tibet you have the facilities to charge you electronic gadgets, where the flow of current and voltage can differ. In Kathmandu / Nepal capacity 609 MW in Integrated Power System, of 230 volts in A.C. single phase and 400 volts in three phases for general. Electricity in Tibet / China is 230 volts AC, 50 cycles. We do have two pins & 3 pins power sockets, you better have two Pin travel plug adapter which will be useful to charge your batteries.
In Tibet where Chinese currency is used, which is about the US $1 equals 6: 50 Chinese Renminbi Yuan, which is the official currency of the People's Republic of China and translates to “people's money.
Tibet, similar to mainland China uses Beijing Standard Time. Which is 8 hours ahead of GMT (Greenwich Mean Time) 2 hours and 15 minutes ahead of Nepal Standard Time Zone.
The chances are small and rare, as you will be spending three overnights in Lhasa at 3,660 m altitude, enough time to get acclimatized before heading towards other higher areas of Tibet, beyond Lhasa. However, some people might catch a slight headache from altitude gain, it will soon recover having rest, drinking enough water that helps to acclimatize from the symptoms of AMS or altitude sickness.
April to May and September and October are the best months for travel to Tibet as well for this tour. The weather is fine and clear most of the season, as the land with high altitude gets much sun for long hours, although cold morning and from late afternoon till night time. Can get very windy especially on the drive to Shigatse during the afternoon time till 4 p.m. Chances of snowfall sometimes around high passes and altitude wise, do get light rain around monsoon time of June to mid-September, but the mostly dry and arid country as weather-wise. Does not get heavy rain like in southern countries of the Himalayas range.