I'm pretty sure the thing being squished between Uguisu and Azuki is a stuffed hippo that Nonoyama Fuu (Mahou no Shimai Lulutto Lilly) has on her bed. This tweet (asset #48610164) shows her room, with a few hippos shown that look very similar.

The cow/hippo thing below them looks very familiar, but I can't read the handwriting and I've not been able to identify it.

I assume the drawing at the top is just the artist herself.

The birds on the left are just a nice pair of tits.