Slightly similar to the Dosu only clan story (we're already filled with awesomeness, so give us reason to take normal yukkuri in)
On topic of Reimu's "specialty" of raising children. Tried imagining, in ideal nicehead no-disaster scenario, what would be the specialty of Reimu-type parenting anyway ? "motherly love" and "emotional understanding" sounds vague.
I imagined a Marisa parent would like to teach physical prowness. Alice parent might be the trendy elder sister-like mother. Patchouli would be focused on education. All in tune with their strongest best quality.
But even then they wouldn't be /that/ polarized. In many nice scenarios, they have capacity of sacrifice regardless of type. They can know and try to soothe their youngs. Patchouli type might handle the situation too logically while Marisa and Alice might be strict (with responsibility and pride) rather than coaxing the children. But that's the only difference I can imagine.
So... in nicehead situation, is Reimu type just like those default preset that's in the middle of everything ? Unfortunately that seems to even amplify the shithead side scenarios (drama queen single mother).
I think Reimu's are basically the Average Mother/Kindergarden Teacher/Nanny of the yukkuris.
And the funny thing is that, unlike other yu's, only a few Reimu's are shown doing stuff like cleaning the nest, sweeping it, etc. At least cleaning it beyond dragging poo away like other yu's do. I had never seen any yu doing the paralel of a housewife sweeping the floor of their home like the nicehead Reimu do from time to time.
Basically Reimu's thing is being good in taking care kids in the traditional and average way, and being good wives, at least that's how the nicehead probably are.
Reimu is good in raising child, let her join the clan.
Even if they're not excellent, Alice and Patchouli can also raise up cute Little Ones.
Reimu is very good at singing.
There's also a lot of way to be easy besides song.
Reimu is cute! Sorry for being cute!
Without saying, everyone is cute in their own way. Personally speaking, Dosu prefer the Alices
Whatever, let Reimu join the clan
Whatever, Reimu can't join the clan