>>14388928yes you can
the way it works you can enter into covenant with all the demonic princesses if you do their quests
frog princess just wants a kiss from you so she is easy
however snow white is a bit different
she wants you to kill the other three
but anyway you get their ring even if you kill them, getting their rings does not need a covenant
>>14388943it just gives a sex scene
also if you have played the redhood game and redhood is your companion you can talk to a frog near the princess for a redhood game reference