Ghost types would need to trust you and respect you, making you equal parts social worker and friend to them.
Fairies also seem to be smarter than most other types, and seem to be mischievous or quirky. I think they'd be as uniquely difficult to raise as Ghost types, and with a whole different set of dangers. Fairies that are predators often do so by manipulating their prey.Rather than having to navigate your Pokemon's feelings like with Ghosts, the difficulty with Fairies is either in how weird they are, or trying to outsmart them before they trick you. Mr. Mime has an alien view of how physical space works. Clefairy have their mysterious moon rituals. Mawile is always trying to bait you into letting it bite your hands off. Sylveon are vicious strangling predators, and Hatterene flip out and violently assault creatures that are loud in their presence. Raising Fairies would be about being on your guard and changing how you think. (This typing might be where Gardevoir's emotional peculiarities are rooted.)
Then, of course, you'd have regulations for mundane types like Fire. Don't want to start any forest fires after all.