It really depends on which version of the canon they're using.
In 2e-era, anything non-human was considered a freak. You had to hide your appearance, or you'd get door shut on you, merchants overcharging you, or mobs waiting to hunt you (depending on the exact nature of your race). This sorta carried over into the Arthaus era RL, but it was a little less overt; it came in large penalties to all non-Intimidate-based Charisma checks ranging from -1 (elf, halfling) to -5 (caliban or weirder).
WotC's only 3e/4e era Ravenloft stuff took a different take; non-humans weren't feared or hated. In Expedition, several NPCs are non-human (including Vistani halflings, a dwarven vampire, elven werewolves, and a half-celestial paladin) and the humans of the Village of Barovia and Strahd himself seem to bear no racial animosity. In 4e, one of the Domains of Dread was based around tieflings and Vistani again could be halflings racially.
My guess is WotC will opt for their 3e/4e version of Barovia and the Domains of Dread and have the races not be singled out for stigma. You could argue maybe some of the more mostrous ones (goliath, tiefling, dragonborn, drow, half-orc) might suffer the minor stigmas that 2e-era elves and halflings endured (overcharging or rude comments) but I don't imagine it will be the same kind of problems 2e demihumans suffered.