For lifty and shifty:

One of member of htf team confirmed that lifty and shifty are "twins" because they were born at same time and both are 28 years old however, if shifty take off his fedora hat and he would be identical as "Lifty"

For Sniffles:

Like real anteaters, he has poorly eyesight then he wearing glasses to helping himself see anything However, he has teeth in his mouth due to cartoon logic unlike real anteater

For flaky:

Flaky was originally created as "male" for a awhile but then this gender has been changed to be female because of her name somehow sounds like female

Flaky is canonically alektorophobia because she's scare of baby chicken it's unknown why she's scare of them it's most likely because if she was scare or something did by that chicken in her early childhood

For handy:

Due to somehow cartoon logic, handy still able to use or do something without hands or arms it can seen in several episodes

His several death, was because lack of arm that he's unable to do something for saving himself or something But if he's still able to do (fact, Due to logic)