Are both biotic and abiotic factors considered part of a population?
Biotic features only
There are generally 6 levels to an ecosystem: Individual, Population, Community, Ecosystem, Biome and Biosphere.
Of them, Population is the second level, and is described as the number of organism in one species who interact and live with each other in the same area. An example would be the number of humans living in London, or the number of polar bears in the Arctic.
Since this definition mentions organisms, Population logically has to include biotic factors. The definition also mentions only organisms interacting with each other, no non-living things, thereby precluding any abiotic factors. Therefore, a Population only includes biotic factors.
I hope I helped!