when will the new characters (for example female dog) or new updates be available?
Oh boy do i have some bad news for you.
For Yiffalicious 1, never.
However, the devs are currently working on a "sequel" that will feature a character creator. They're aiming to release a playable version of said character creator for backers by the end of the year, though it remains to be seen if they can make that deadline. You can take a look at the Patreon updates they've been posting to get an idea of what it will be capable of, some fairly interesting stuff: