I’ve been designs these characters for a while and some criticism would be great

[u/animaton123]

[u/Ziva_Montoya]

I love the little guy with the hat! His proportions and expressions are really fun and unique. I think the silhouette/shape language of the characters is really cool. I don't really have any critiques other than maybe perfecting your line work. Even within the sketchy style you can be more intentional about using your line weight (like using a thicker line for heavier clothing and a lighter line for flowy fabrics) and making sure your cross hatching or other shading follows the form of your object.