Those numbers could be "doubled".
I mean, I get that they're odd numbers and hence not multiples of 2. However I would assume that as with the buddy not literally giving 4x candy but getting the same candy 4x faster, the hatched pokemon aren't literally giving 2x candy but are calculating the random amount of candy within 2x limits.
i.e. if a hatched exeggcute would normally give 10-18 Candy, it will now give 20-36 candy. 21 falls within that range (whereas 21 sounds awfully high for a non-adjusted Exeggcute hatch).
Likewise, perhaps a Jynx could give 17-24 candy beforehand, and now it can give 34-48. I hatched a Jynx for 17 candy before the event was announced, so 35 candy seems awfully high to me again without a multiplier.