So a user i know got permabanned for "ban evasion" i checked the account that was accused of being the banned account and found inconsistencies with the two if there is evidence can the ban be reversed?

Doubtful, permabans are usually...well, permanent. But don't take my word for it.

If there's actually any evidence that they're not the same person they can probably appeal with the email address on the contact page.

I'm not sure that the staff would ban anybody for ban evasion with any evidence, so I doubt an appeal would do much.