The original translated text does not describe how Reimu fed Marisa the medicine but it is implied to be the tongue to mouth approach mother yukkuris do for their babies.
I originally planned to insert Mima and Mystia in there but I decided not to. The original plan was to depict a scene of winged yukkuri migrating and I think 3 winged yus at various elevations is enough to depict that.
Making shinki's wings is a pain. Sariel's wings originally had more details but I decided to scrap it. Momiji's tail looks blocky after I compress the size as it originally looks too big for her.
For what I initially thought was a series where I will put in shitty art in a pump and dump type of approach, I actually now care about how it looks.
I still suck at drawing though >=P