I decided to trial out low poly modelling first on the penguin, as I thought it wasn't an overly complicated animal to try and create. I found some studies of penguins online which were very clear with proportion, and I roughly used these to base my model off, though did simplify and had to guess a little. This is the base model I ended up with, I tried to keep it as simple as possible while still being recognisable, but kept in mind that I would need to be unfolding and physically putting together these meshes too, so it couldn't be too complicated, plus I still had to trial out low poly methods.
I duplicated the model a few times and hardened the edges.
The next method I tried was to reduce the polygons, I played around with different settings and percentages to see what I could do.
For the 2nd in on the right I first triangulated and then reduced by 30% too.
My favourite outcomes are the far right front, which was a reduction of 50%, but then the back view of the middle one, which was a reduction of 30%, so I combined them together.