About the Manaslu Region
Until very recently Manaslu had no teahouse lodges, and trekkers had to take a camp and crew. Relatively few did, and Manaslu was usually considered a Remote Area trek, despite its location between the Annapurna Massif and the Langtang region.
Now it's possible to stay in teahouses, and perhaps an occasional home stay. Trekkers to Tsum might want to have a tent and some dried foods as a margin, but within a year or two that won't be necessary.
The teahouses mean that many more trekkers are coming, and things will change. If you are interested in Manaslu, do it soon. Right now it's like the Annapurna Circuit trek was in the 1980s - the real Nepal but with just enough infrastructure to make lightweight trekking possible.
There's a lot of variety: The lower reaches of trail pass through Hindu Nepal, but above Jagat you will be in Buddhist areas. In fact many of the high-mountain dwellers are Tibetans who moved across the border after the Chinese invasion in 1950.